Oracle® Linux
Release Notes for Unbreakable Enterprise Kernel Release 3 Quarterly
Update 4
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E58283-01
December 2014
Abstract
This document contains information on Quarterly Update 4 to
the Unbreakable Enterprise Kernel Release 3. This document
may be updated after it is released. To check for updates to
this document, and to view other Oracle documentation, refer
to the Documentation section on the Oracle Technology Network
(OTN) Web site:
http://www.oracle.com/technology/documentation/
This document is intended for users and administrators of
Oracle Linux. It describes potential issues and the
corresponding workarounds you may encounter while using the
Unbreakable Enterprise Kernel Release 3 with Oracle Linux 6
or Oracle Linux 7. Oracle recommends that you read this
document before installing or upgrading the Unbreakable
Enterprise Kernel Release 3.
Document generated on: 2014-12-04 (revision: 2451)
________________________________________________________
Preface
The Oracle Linux Unbreakable Enterprise Kernel Release Notes
provides a summary of the new features, changes, and fixed
and known issues in the Unbreakable Enterprise Kernel Release
3.
Audience
This document is written for system administrators who want
to use the Unbreakable Enterprise Kernel with Oracle Linux.
It is assumed that readers have a general understanding of
the Linux operating system.
Documentation Accessibility
For information about Oracle's commitment to accessibility,
visit the Oracle Accessibility Program website at
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Oracle Support. For information, visit
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if you are hearing impaired.
Related Documents
The latest version of this document and other documentation
for this product are available at:
http://www.oracle.com/technetwork/server-storage/linux/docume
ntation/index.html.
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that you enter.
Chapter 1 New Features and Changes
The Unbreakable Enterprise Kernel Release 3 (UEK R3) is
Oracle's third major release of its heavily tested and
optimized operating system kernel for Oracle Linux 6 and 7 on
the x86-64 architecture. It is based on the mainline Linux
kernel version 3.8.13.
The 3.8.13-55 release is the fourth quarterly update release
for UEK R3. It includes security and bug fixes, as well as
driver updates.
Oracle actively monitors upstream checkins and applies
critical bug and security fixes to UEK R3.
UEK R3 uses the same versioning model as the mainline Linux
kernel version. It is possible that some applications might
not understand the 3.x versioning scheme. If an application
does require a 2.6 context, you can use the uname26 wrapper
command to start it. However, regular Linux applications are
usually neither aware of, nor affected by, Linux kernel
version numbers.
1.1 Notable Changes
* Automatic loading of DTrace modules. You can now specify
entries in /etc/dtrace-modules that define the modules
that DTrace should load automatically when it starts. For
example:
# The modules to be loaded follow this comment, one per line
profile
systrace
sdt
fasttrap
For more information about the modules and providers that
are included with the Oracle Linux implementation of
DTrace, see the Oracle Linux DTrace Tutorial
(http://docs.oracle.com/cd/E37670_01/E50705/html/ol_diffs
_dtrace.html).
* PMC-Sierra PM8001 SAS/SATA controller driver (pm8001) has
been added. This driver supports the new Adaptec Series
7H family of 8-port and 16-port PCIe gen3 SAS/SATA host
bus adapters.
* Intel XL710 X710 Virtual Function network driver (i40evf)
has been added.
* The P-state driver (intel_pstate) for the Intel Sandy
Bridge processor has been added.
* Various network performance improvement patches to
support Oracle Linux virtual machines running on
Microsoft Hyper-V.
* New kernel event actions (uevents) are generated when
certain SCSI ASC/ASCQ unit attention codes are received,
see the kernel change log
(http://git.kernel.org/cgit/linux/kernel/git/torvalds/lin
ux.git/commit/?id=279afdfe78a020b4b1a68bffd0009b961b12982
e ) for details. You can configure your own udev rules to
handle these events, as there is no default processing.
* NFS over Remote Data Memory Access (RDMA) Client is
available as a technology preview. See Section 1.4,
"Technology Preview" for more detail.
1.2 Xen Improvements
* Support for Xen UEFI hypercall.
* Backport of fixes and features from Xen Linux 3.17.
* Backport of syncing CMOS real-time clock (RTC) as well as
Xen wallclock.
* Xen pciback fixes for PCI passthrough.
* Backport xen_nopv parameter to disable PV extensions for
HVM guests.
1.3 Driver Updates
The Unbreakable Enterprise Kernel supports a wide range of
hardware and devices. In close cooperation with hardware and
storage vendors, several device drivers have been updated by
Oracle.
1.3.1 Storage Adapter Drivers
Broadcom
* NetXtreme II Fibre Channel over Ethernet driver (bnx2fc)
updated to 2.5.5.1.
* NetXtreme II iSCSI driver (bnx2i) updated to 2.7.10.31d1.
Emulex
* OneConnect (previously known as Blade Engine 2)
Open-iSCSI driver (be2iscsi) updated to 10.4.114.0o.
* LightPulse Fibre Channel SCSI (previously known as Fibre
Channel HBA) driver (lpfc) updated to 0:10.2.8061.0.
HP
* Upstream patches have been applied to the HP Smart Array
CCISS driver (cciss). The driver version number is
unchanged.
* Upstream patches have been applied to the HP Smart Array
Controller driver (hpsa) The driver version number is
unchanged.
Intel
* Upstream patches have been applied to the NVM Express
device driver (nvme). The driver version number is
unchanged.
LSI
* Upstream patches have been applied to the Fusion MPT SAS
host driver (mptsas). The driver version number is
unchanged.
* Upstream patches have been applied to the LSI MegaRAID
SAS driver (megaraid_sas). The driver version number is
unchanged.
PMC
* PMC-Sierra PM8001 SAS/SATA controller driver (pm8001)
version 0.1.36 added.
QLogic
* Fibre Channel HBA driver (qla2xxx) updated to
8.07.00.16.39.0-k.
1.3.2 Network Adapter Drivers
Broadcom
* NetXtreme II 1 Gigabit network adapter driver (bnx2)
updated to 2.2.5i.
* NetXtreme II 10 Gigabit network adapter driver (bnx2x)
updated to 1.710.51.
* NetXtreme II Converged Network Interface Card core driver
(cnic) updated to 2.5.20b.
* Upstream patches have been applied to the Tigon3 Ethernet
adapter driver (tg3). The driver version number is
unchanged.
Emulex
* OneConnect (previously known as Blade Engine 2) NIC
driver (be2net) updated to 10.4u.
Intel
* Gigabit Virtual Function driver (igbvf) updated to 2.3.5.
* 10 Gigabit PCI Express network driver (ixgbe) updated to
3.22.3.
* 10 Gigabit PCI Express virtual function driver (ixgbevf)
updated to 2.15.3.
* Ethernet Connection XL710 Network Driver (i40e) updated
to 0.3.43-k.
* XL710 X710 Virtual Function network driver (i40evf)
version 0.9.21 added.
QLogic
* 1/10 GbE Converged/Intelligent Ethernet adapter driver
(qlcnic) updated to 5.3.62.
* Upstream patches have been applied to the 10 Gigabit
PCI-E Ethernet adapter driver (qlge). The driver version
number is unchanged.
* Upstream patches have been applied to the NetXen (1/10)
Gigabit Intelligent Ethernet driver (netxen_nic). The
driver version number is unchanged.
1.3.3 Miscellaneous Drivers
Intel
* The P-state driver (intel_pstate) for the Intel Sandy
Bridge processor has been added to UEK R3. In cpufreq
terminology, this driver implements a scaling driver with
an internal governor.
To enable the intel_pstate driver on Sandy Bridge or
later processors, you can blacklist preferred cpufreq
drivers such as acpi-cpufreq by running the following
command:
# echo 'blacklist acpi-cpufreq' > /etc/modprobe.d/cpufreq.conf
Caution
Unlike the acpi-cpufreq driver, the intel_pstate driver
does not support the CPU power capping feature on Oracle
Sun x86 Servers.
1.4 Technology Preview
The following features included in the Unbreakable Enterprise
Kernel Release 3 are still under development, but are made
available for testing and evaluation purposes.
* DRBD (Distributed Replicated Block Device)
A shared-nothing, synchronously replicated block device
(RAID1 over network), designed to serve as a building
block for high availability (HA) clusters. It requires a
cluster manager (for example, pacemaker) for automatic
failover.
* Kernel module signing facility
Applies cryptographic signature checking to modules on
module load, checking the signature against a ring of
public keys compiled into the kernel. GPG is used to do
the cryptographic work and determines the format of the
signature and key data.
* Transcendent memory
Transcendent Memory (tmem) provides a new approach for
improving the utilization of physical memory in a
virtualized environment by claiming underutilized memory
in a system and making it available where it is most
needed. From the perspective of an operating system, tmem
is fast pseudo-RAM of indeterminate and varying size that
is useful primarily when real RAM is in short supply. To
learn more about this technology and its use cases, see
the Transcendent Memory project page at
http://oss.oracle.com/projects/tmem/.
* NFS over RDMA Client
Enables you to use NFS over the RDMA transport on the
Oracle InfiniBand stack. This is more efficient than
using the TCP/IPoIB transport. The technology preview
does not include NFS over RDMA server support, or support
for NFS over RDMA in virtualized environments. NFS
version 3 and 4 are supported. Currently, only the
Mellanox ConnectX-2 and ConnectX-3 Host Channel Adapters
(HCAs) are supported. The client passes the full
Connectathon NFS test suite using these HCAs. The Release
Notes will be updated if additional adapters are
supported after the initial release.
See Section 1.4.1, "Using the NFS over RDMA Client" for
details of how to use the feature.
1.4.1 Using the NFS over RDMA Client
The following instructions also include details for enabling
an NFS over RDMA server. These are provided as an example
only, as the NFS over RDMA server is currently not supported
with the UEK R3 kernel.
1. Install an RDMA device, set up InfiniBand and enable
IPoIB.
The Oracle Linux OFED packages are available from the
following channels:
+ Oracle Linux 6: ol6_x86_64_ofed_UEK
+ Oracle Linux 7: ol7_x86_64_UEKR3_OFED20
2. Check that the RDMA device is working.
# cat /sys/class/infiniband/driver_name/ports/1/state
4: ACTIVE
where driver_name is the RDMA device driver, for example
mlx4_0.
3. Verify the physical InfiniBand interfaces and links.
Check that the hosts can be contacted through the
InfiniBand switch, by using commands such as ibhosts, and
ibnetdiscover.
4. Check the connection between the NFS client and NFS
server.
You can configure the settings for an InfiniBand
interface in the
/etc/sysconfig/network-scripts/ifcfg-ibN file.
You can use the ping command to check the connection. For
example:
nfs-server$ ip addr add 10.196.0.101/24 dev ib0
nfs-client$ ip addr add 10.196.0.102/24 dev ib0
nfs-server$ ping 10.196.0.102
nfs-client$ ping 10.196.0.101
5. Install the nfs-utils package on the NFS client and
server.
6. Configure the NFS shares.
Edit the /etc/exports file. Define the directories that
the NFS server will make available for clients to mount,
using the IPoIB addresses of the clients. For example:
/export_dir 10.196.0.102(fsid=0,rw,async,insecure,no_root_squash)
/export_dir 10.196.0.0/255.255.255.0(fsid=0,rw,async,insecure,no_root_
squash)
7. On the NFS server, load the svcrdma kernel module and
start the NFS service.
Oracle Linux 6:
# modprobe svcrdma
# service nfs start
# echo rdma 20049 > /proc/fs/nfsd/portlist
Oracle Linux 7:
# modprobe svcrdma
# systemctl start nfs-server
# echo rdma 20049 > /proc/fs/nfsd/portlist
Note
The rdma 20049 setting does not persist when the NFS
service is restarted. You have to set it each time the
NFS service starts.
8. On the NFS client, load the xprtrdma kernel module and
start the NFS service.
# modprobe xprtrdma
# service nfs start
# mount -o proto=rdma,port=20049 host:/export /mnt
where host is the host name or IP address of the IPoIB
server, and export is the name of the NFS share.
To check that the mount over RDMA is successful, check
the proto field for the mount point.
# nfsstat -m
/mnt from 10.196.0.102:/export
Flags: rw,relatime,vers=4.0,rsize=262144,wsize=262144,namlen=255,hard,
proto=rdma,port=20049,
...
Alternatively:
# cat /proc/mounts
Known Issues
Any mounted file systems must be unmounted on the NFS client
before you shut down the NFS server. Otherwise the NFS server
hangs when you shut down.
1.5 Compatibility
Oracle Linux maintains user-space compatibility with Red Hat
Enterprise Linux, which is independent of the kernel version
running underneath the operating system. Existing
applications in user space will continue to run unmodified on
the Unbreakable Enterprise Kernel Release 3 and no
re-certifications are needed for RHEL certified applications.
To minimize impact on interoperability during releases, the
Oracle Linux team works closely with third-party vendors
whose hardware and software have dependencies on kernel
modules. The kernel ABI for UEK R3 will remain unchanged in
all subsequent updates to the initial release. In this
release, there are changes to the kernel ABI relative to UEK
R2 that require recompilation of third-party kernel modules
on the system. Before installing UEK R3, verify its support
status with your application vendor.
1.6 Header Packages for Development
The kernel-headers packages provide the C header files that
specify the interface between user-space binaries or
libraries and UEK or RHCK. These header files define the
structures and constants that you need to build most standard
programs or to rebuild the glibc package.
The kernel-devel and kernel-uek-devel packages provide the
kernel headers and makefiles that you need to build modules
against UEK and RHCK.
Chapter 2 Fixed and Known Issues
This chapter describes the fixed and known issues for the
Unbreakable Enterprise Kernel Release 3.
Important
Run the yum update command regularly to ensure that the
latest bug fixes and security errata are installed on your
system.
2.1 Fixed Issues
The following issues have been fixed in this update.
bnx2i Driver
* Fixed the issue with the bnx2i driver that caused a
kernel panic when the iscsiadm command is used. (Bug
19726959)
DTrace
* Dtrace modules can now be loaded automatically. (Bug ID
19821254)
* If initial process grabs or creations fail, they no
longer cause intermittent core dumps. (Bug ID 19679998)
* It was possible for an executed process to terminate
abnormally if DTrace user-space tracing was already
active.
* DTrace could lose track of the state of a process, or
even become deadlocked, if the process called exec()
while DTrace was inserting a breakpoint.
ext3
* The problem that caused file system corruption in a
virtual machine when the virtual disks are configured as
sparse files in an ext3 repository has been fixed. (Bug
ID 19220057)
Hyper-V
* Reloading Hyper-V kernel modules using modprobe no longer
results in a kernel panic.
* The Kdump kernel crash feature now works as expected in
Oracle Linux virtual machines on Windows Server 2012 R2
hosts. (Bug 19727047)
* The hot-adding memory feature now works with Oracle Linux
virtual machines. (Bug 19441989)
Microcode
* Systems with Haswell CPUs no longer experience lengthy
boot delays due to microcode loading issues.
nvme Driver
* Fixed the bug with the nvme driver that caused
hot-unplugged and re-plugged devices to show up with zero
capacity and an erroneous detected capacity change
message in /var/log/messages. (Bug 19566288)
OCFS2
* OCFS2 no longer hangs due to a wrong locking order. (Bug
ID 19547845, 19249791)
* Enabling the global heartbeat no longer causes a node to
reboot when the cluster configuration (cluster.conf) is
inconsistent across the stack. (Bug 19549715)
qla2xxx Driver
* Fixed incorrectly returned PCI EEH busy warning message.
(Bug ID 19916135)
Virtualization
* Increasing the number of virtual CPUs on a running PVM
guest (xm vcpu-set) no longer causes a soft lockup. (Bug
19261720)
* Shutting down or rebooting a PVM guest no longer causes a
kernel panic. (Bug 19803968)
XFS
* Turning project quotas off with xfs_quota no longer fails
with an XFS_QUOTARM: Invalid argument error. (Bug ID
19815141)
2.2 Known Issues
This section describes the known issues in this update.
ACPI
The following messages indicate that the BIOS does not
present a suitable interface, such as _PSS or _PPC, that the
acpi-cpufreq module requires:
kernel: powernow-k8: this CPU is not supported anymore, using acpi-cpu
freq instead.
modprobe: FATAL: Error inserting acpi_cpufreq
There is no known workaround for this error. (Bug ID
17034535)
btrfs
* If you use the --alloc-start option with mkfs.btrfs to
specify an offset for the start of the file system, the
size of the file system should be smaller but this is not
the case. It is also possible to specify an offset that
is higher than the device size. (Bug ID 16946255)
* The usage information for mkfs.btrfs reports raid5 and
raid6 as possible profiles for both data and metadata.
However, the kernel does not support these features and
cannot mount file systems that use them. (Bug ID
16946303)
* The btrfs filesystem balance command does not warn that
the RAID level can be changed under certain
circumstances, and does not provide the choice of
cancelling the operation. (Bug ID 16472824)
* Converting an existing ext2, ext3, or ext4 root file
system to btrfs does not carry over the associated
security contexts that are stored as part of a file's
extended attributes. With SELinux enabled and set to
enforcing mode, you might experience many permission
denied errors after reboot, and the system might be
unbootable. To avoid this problem, enforce automatic file
system relabeling to run at bootup time. To trigger
automatic relabeling, create an empty file named
.autorelabel (for example, by using touch) in the file
system's root directory before rebooting the system after
the initial conversion. The presence of this file
instruct SELinux to recreate the security attributes for
all files on the file system. If you forget to do this
and rebooting fails, either temporarily disable SELinux
completely by adding selinux=0 to the kernel boot
parameters, or disable enforcing of the SELinux policy by
adding enforcing=0. (Bug ID 13806043)
* Commands such as du can show inconsistent results for
file sizes in a btrfs file system when the number of
bytes that is under delayed allocation is changing. (Bug
ID 13096268)
* The copy-on-write nature of btrfs means that every
operation on the file system initially requires disk
space. It is possible that you cannot execute any
operation on a disk that has no space left; even removing
a file might not be possible. The workaround is to run
sync before retrying the operation. If this does not
help, remount the file system with the -o nodatacow
option and delete some files to free up space. See
https://btrfs.wiki.kernel.org/index.php/ENOSPC.
* On Oracle Linux 6, btrfs has a limit of 237 or fewer hard
links to a file from a single directory. The exact limit
depends on the number of characters in the file name. The
limit is 237 for a file with up to eight characters in
its file name; the limit is lower for longer file names.
Attempting to create more than this number of links
results in the error Too many links. You can create more
hard links to the same file from another directory.
Although the limitation of the number of hard links in a
single directory has been increased to 65535, the version
of mkfs.btrfs that is provided in the btrfs-progs package
does not yet support the compatibility flag for this
feature. Oracle Linux 7 includes a later version of
btrfs-progs package, which does support the increased
number of hard links. (Bug ID 16285431)
* If you run the btrfs quota enable command on a non-empty
file system, any existing files do not count toward space
usage. Removing these files can cause usage reports to
display negative numbers and the file system to be
inaccessible. The workaround is to enable quotas
immediately after creating the file system. If you have
already written data to the file system, it is too late
to enable quotas. (Bug ID 16569350)
* The btrfs quota rescan command is not currently
implemented. The command does not perform a rescan and
returns without displaying any message. (Bug ID 16569350)
* When you overwrite data in a file, starting somewhere in
the middle of the file, the overwritten space is counted
twice in the space usage numbers that btrfs qgroup show
displays. (Bug ID 16609467)
* If you run btrfsck --init-csum-tree on a file system and
then run a simple btrfsck on the same file system, the
command displays a Backref mismatch error that was not
previously present. (Bug ID 16972799)
* If you use the -s option to specify a sector size to
mkfs.btrfs that is different from the page size, the
created file system cannot be mounted. By default, the
sector size is set to be the same as the page size. (Bug
ID 17087232)
* Defragmentation can break data block sharing. Due to the
copy-on-write design of btrfs, snapshots initially share
the same data blocks of the original subvolume. However,
when either the snapshot or the subvolume is
defragmented, this sharing can be undone, resulting in a
higher disk space usage.
dm-nfs Module Obsolete
In UEK R2, the dm-nfs module provided the ability to create a
loopback device for a mounted NFS file or file system. For
example, the feature allowed you to create the shared storage
for an Oracle 3 VM cluster on an NFS file system. The dm-nfs
module provided direct I/O to the server and bypassed the
loop driver to avoid an additional level of page caching. The
dm-nfs module is not provided with UEK R3. The loop driver
can now provide the same I/O functionality as dm-nfs by
extending the AIO interface to perform direct I/O. To create
the loopback device, use the losetup command instead of
dmsetup.
DTrace
* Using kill -9 to terminate dtrace can leave breakpoints
outstanding in processes being traced, which might sooner
or later kill them.
* Argument declarations for probe definitions cannot be
declared with derived types such as enum, struct, or
union.
* The following compiler warning can be ignored for probe
definition arguments of type string (which is a D type
but not a C type):
provider_def.h:line#: warning: parameter names (without types) in func
tion declaration
ERST Message
You can safely ignore the following message that might be
displayed in syslog or dmesg:
ERST: Failed to get Error Log Address Range.
The message indicates that the system BIOS does not support
an Error Record Serialization Table (ERST). (Bug ID 17034576)
Ext4
The inline data feature that allows the data of small files
to be stored inside their inodes is not yet available. The -O
inline_data option to the mkfs.ext4 and tune2fs commands is
not supported. (Bug ID 17210654)
Firmware Warning Message
You can safely ignore the following firmware warning message
that might be displayed on some Sun hardware:
[Firmware Warn]: GHES: Poll interval is 0 for generic hardware error s
ource:
1, disabled.
(Bug ID 13696512)
Huge Pages
One-gigabyte (1 GB) huge pages are not currently supported
for the following configurations:
* HVM guests
* PV guests
* Oracle Database
Two-megabyte (2 MB) huge pages have been tested and work with
these configurations.
(Bug ID 17299364, 17299871, 17271305)
Hyper-V
The following known issues affect Oracle Linux virtual
machines running on Hyper-V:
* After you take a snapshot of a virtual machine and then
use the Save action to save the virtual machine state,
you might not be able to revert to the virtual machine to
the snapshot using the Revert action. The workaround is
to click on the last snapshot listed in the Snapshot area
for the virtual machine, and then select Apply. (Bug ID
20110077)
* Oracle Linux 7 virtual machines that use Legacy Network
mode lose their network connectivity if more than one
virtual CPU is configured. The workaround is to configure
only one virtual CPU for Oracle Linux 7 virtual machines.
(Bug ID 20110058)
* Oracle Linux 6 virtual machines running on Windows Server
2012R2 display truncated messages during a system
shutdown or reboot. (Bug ID Bug 20090500)
* With Windows Server 2008R2, if you hot-add a VHD disk
using a SCSI controller, the disk is detected multiple
times after the virtual machine is rebooted. (Bug ID
19706977)
I/O Scheduler
The Unbreakable Enterprise Kernel uses the deadline scheduler
as the default I/O scheduler. For the Red Hat Compatible
Kernel, the default I/O scheduler is the cfq scheduler.
ioapic Failure Messages
You can safely ignore messages such as ioapic: probe of
0000:00:05.4 failed with error -22. Such messages are the
result of the ioapic driver attempting to re-register I/O
APIC PCI devices that were already registered at boot time.
(Bug ID 17034993)
InfiniBand
* You might see the following warning messages if you use
the ibportstate disable command to disable a switch port:
ibwarn: [2696] _do_madrpc: recv failed: Connection timed out
ibwarn: [2696] mad_rpc: _do_madrpc failed; dport (Lid 38)
ibportstate: iberror: failed: smp set portinfo failed
You can safely ignore these warnings. (Bug ID 16248314)
* The Internet Protocol over InfiniBand (IPoIB) driver
supports the use of either connected mode or datagram
mode with an interface, where datagram mode is the
default mode. Changing the mode of an InfiniBand
interface by echoing either connected or datagram to
/sys/class/net/ibN/mode is not supported. It is also not
possible to change the mode of an InfiniBand interface
while it is enabled.
To change the IPoIB mode of an InfiniBand interface:
1. Edit the /etc/sysconfig/network-scripts/ifcfg-ibN
configuration file, where N is the number of the
interface:
o To configure connected mode, specify
CONNECTED_MODE=yes in the file.
o To configure datagram mode, either specify
CONNECTED_MODE=no in the file or do not specify
this setting at all (datagram mode is enabled
by default).
Note
Before saving your changes, make sure that you have
not specified more than one setting for
CONNECTED_MODE in the file.
2. To enable the specified mode on the interface, use
the following commands to take down the interface
and bring it back up:
# ifdown ibN
# ifup ibN
(Bug ID 17479833)
* When the rds_ib_srq parameter for the rds_rdma module is
enabled and the module is in use (for example when
running the rds-stress tool), restarting the rdma service
(which reloads the rds_rdma module) generates error
messages visible in dmesg or /var/log/messages. (Bug ID
18243427)
Linux Containers (LXC)
* The root user in a container can affect the configuration
of the host system by setting some /proc entries. (Bug ID
17190287)
* Using yum to update packages inside the container that
use init scripts can undo changes made by the Oracle
template.
* Migrating live containers (lxc-checkpoint) is not yet
supported.
* Oracle Database is not yet supported for use with Linux
Containers. The following information is intended for
those who want to experiment with such a configuration.
The following /proc parameter files may only be set on
the host and not for individual containers:
+ /proc/sys/fs/aio-max-nr
+ /proc/sys/net/core/rmem_default
+ /proc/sys/net/core/rmem_max
+ /proc/sys/net/core/wmem_default
+ /proc/sys/net/core/wmem_max
+ /proc/sys/net/ipv4/ip_local_port_range
Setting the parameters in the host to the Oracle
recommended values sets them for all containers and
allows the Oracle database to run in a container. For
more information, see Configuring Kernel Parameters and
Resource Limits
(http://docs.oracle.com/cd/E11882_01/install.112/e24326/t
oc.htm#BHCCADGD). (Bug ID 17217854)
* If a Device or resource busy - failed to set
memory.use_hierarchy to 1 error message is displayed when
you start a container, edit the /etc/cgconfig.conf file
and add the following:
group . {
memory {
memory.use_hierarchy = "1";
}
}
(Bug ID 19237222)
Missing Documentation for PCIe Kernel Parameters
The following documentation for some PCIe kernel parameters
is not included in the kernel-parameters.txt file in the
kernel-uek-doc package:
pcie_bus_tune_off
Disable PCIe MPS (Max Payload Size) tuning and use the
BIOS-configured MPS defaults.
pcie_bus_safe
Set every device's MPS to the largest value supported
by all devices below the root complex.
pcie_bus_perf
Set device MPS to the largest allowable MPS based on
its parent bus. Also set MRRS (Max Read Request Size)
to the largest supported value (no larger than the MPS
that the device or bus can support) for best
performance.
pcie_bus_peer2peer
Set every device's MPS to 128B, which every device is
guaranteed to support. This configuration allows
peer-to-peer DMA between any pair of devices, possibly
at the cost of reduced performance. This also
guarantees that hot-added devices will work.
Mellanox Driver (mlx4_en)
The Mellanox mlx4_en driver fails to auto-sense the data link
and, as a result, the driver is not automatically loaded.
(Bug ID 20103438)
RDMA Does Not Load the mlx4_ib Module
If you enable the OFED stack and the RDMA service but the
version of the RDMA package is lower than
rdma‑3.10‑3.0.2.el6, the RDMA service does not load the
mlx4_ib module automatically.
To configure the RDMA service to load the mlx4_ib module at
boot time:
1. Edit /etc/rdma/rdma.conf and set the entry MLX4_LOAD=yes
in this file.
2. To make the change take effect, restart the RDMA service
or reboot the system.
sched_yield() Settings for CFS
For the Unbreakable Enterprise Kernel,
kernel.sched_compat_yield=1 is set by default. For the Red
Hat Compatible Kernel, kernel.sched_compat_yield=0 is used by
default.
Slow Performance With Multipath Devices
Starting with UEK R2, the device mapper has had the
capability to check whether the underlying storage device has
advertised the need to flush the data that resides in the
device's cache to its non-volatile storage. For a data
integrity operation, such as fsync and sync, the operation
will now need to include the time to flush the device's cache
(if it is advertised). Such an operation will appear to be
slower when compared to a previous older kernel, however this
is the correct behavior. (Bug ID 17823743)
Soft Lockup Errors When Booting
When upgrading or installing the UEK R3 kernel on fast
hardware, usually with SAN storage attached, the kernel can
fail to boot and BUG: soft lockup messages are displayed in
the console log. The workaround is to increase the baud rate
from the default value of 9600 by amending the kernel boot
line in /boot/grub/grub.conf to include an appropriate
console setting, for example:
console=ttyS0,115200n8
A value of 115200 is recommended as smaller values such as
19200 are known to be insufficient for some systems (for
example, see
http://docs.oracle.com/cd/E19045-01/blade.x6220/820-0048-18/s
p.html#0_pgfId-1002490). If the host implements an integrated
system management infrastructure, such as ILOM on Sun and
Oracle systems or iLO on HP systems, configure the integrated
console baud rate to match the setting for the host system.
Otherwise, the integrated console is likely to display
garbage characters. (Bug ID 17064059, 17252160)
Transparent Huge Pages
The Transparent Huge Pages (THP) feature is disabled.
Following extensive benchmarking and testing, Oracle found
that THP caused a performance degradation of between 5 and
10% for some workloads. This performance degradation was a
result of a slower memory allocator code path being used even
when the applications were not using THP. When the fact that
huge pages are not swappable was taken into account, the
positive effect that THP should provide was outweighed by its
negative effects.
After installing this UEK release, you cannot enable THP (for
example, by specifying kernel boot parameters). The THP
settings under /sys/kernel/mm/transparent_hugepage have also
been removed. A future update might contain an updated THP
implementation which resolves the performance issue.
Note
This change does not affect support for applications that use
explicit huge pages (for example, Oracle Database).
(Bug ID 16823432)
User Namespaces
The kernel functionality (CONFIG_USER_NS) that allows
unprivileged processes to create namespaces for users inside
which they have root privileges is not currently implemented
because of a clash with the implementation of XFS. This
functionality is primarily intended for use with Linux
Containers. As a result, the lxc-checkconfig command displays
User namespace: missing. (Bug ID 16656850)
Virtualization
* When booting UEK R3 as a PVHVM guest, you can safely
ignore the following kernel message:
register_vcpu_info failed:
err=-38
(Bug ID 13713774)
* Under Oracle VM Server 3.1.1, migrating a PVHVM guest
that is running the UEK R3 kernel causes a disparity
between the date and time as displayed by date and
hwclock. To prevent this from occurring, upgrade to
Oracle VM Server 3.2.1 or later. The workaround post
migration is either to run the command hwclock --hctosys
on the guest or to reboot the guest. (Bug ID 16861041)
* On virtualized systems that are built on Xen version 3,
including all releases of Oracle VM 2 including 2.2.2 and
2.2.3, disk synchronization requests for ext3 and ext4
file systems result in journal corruption with kernel
messages similar to the following being logged:
blkfront: barrier: empty write xvda op failed
blkfront: xvda: barrier or flush: disabled
In addition, journal failures such as the following might
be reported:
Aborting journal on device xvda1
The workaround is to add the mount option barrier=0 to
all ext3 and ext4 file systems in the guest VM before
upgrading to UEK R3. For example, you would change a
mount entry such as:
UUID=4e4287b1-87dc-47a8-b69a-075c7579eaf1 / ext3 defaults 1 1
so that it reads:
UUID=4e4287b1-87dc-47a8-b69a-075c7579eaf1 / ext3 defaults,barrier=0
1 1
This issue does not apply to Xen 4 based systems, such as
Oracle VM 3. (Bug ID 17310816)
* Xen does not support the crashkernel=auto parameter for
Kdump configuration. (Bug ID 18174580)
* Mounting or changing an ISO image in a PVHVM guest
results in exception messages in the Oracle VM console.
The ISO image itself is mounted correctly and is
accessible. (Bug ID 19972081)
* You cannot increase (hot plug) the number of virtual CPUs
in a running Oracle Linux 7 guest using the xm vcpu-set
command. Decreasing the number of virtual CPUs does work.
(Bug ID 18865156)
X.509 Certificates for Module Verification
The system reports a message similar to the following if
there is a problem loading an in-kernel X.509 module
verification certificate at boot time:
Loading module verification certificates
X.509: Cert 0c21da3d73dcdbaffc799e3d26f3c846a3afdc43 is not yet valid
MODSIGN: Problem loading in-kernel X.509 certificate (-129)
This error occurs because the hardware clock lags behind the
system time as shown by hwclock, for example:
# hwclock
Tue 20 Aug 2013 01:41:40 PM EDT -0.767004 seconds
The solution is to set the hardware clock from the system
time by running the following command:
# hwclock --systohc
After correcting the hardware clock, no error should be seen
at boot time, for example:
Loading module verification certificates
MODSIGN: Loaded cert 'Slarti: Josteldalsbreen signing key:
0c21da3d73dcdbaffc799e3d26f3c846a3afdc43'
(Bug ID 17346862)
XFS
* In some circumstances, xfsdump can fail when the file
system to be backed up is specified as a mount point, for
example:
xfsdump: ERROR: /mnt/myxfs/ does not identify a file system
The workaround is to specify the file system by its
device name, for example /dev/sdb. (Bug ID 18483275)
* In a virtual machine, the intensive direct I/O on files
which are being fragmented by fallocate and punch_hole in
parallel may result, in some circumstances, in data
corruption with the error Invalid or incomplete multibyte
or wide character. (Bug ID 18711409)
* The following message might be displayed when you use the
xfs_growfs command:
xfs_growfs: cannot find mount point for path `mount_point': Success
The message is caused by an incorrect mounted project
path listed in the XFS project quota initialization file,
/etc/projects. If you are not using project quotas,
remove the /etc/projects file. (Bug ID 18886520)
* On Oracle Linux 6, an XFS file system can become
corrupted if all of its inodes are used. (Bug ID
19217280)
* On Oracle Linux 7, a kernel panic can occur if all the
inodes for an XFS file system are used. (Bug ID 19695297)
* On Oracle Linux 7, xfs_copy fails to copy a file system
if the device sector size more than 512 bytes. (Bug ID
19267663)
* xsf_repair causes a segmentation fault when you try
repair a file system using a short reporting interval
(-t).
Chapter 3 Installation and Availability
Unbreakable Enterprise Kernel Release 3 (UEK R3) is only
supported on the x86-64 architecture.
Oracle Linux 7
UEK R3 is the default boot kernel for fresh installations of
Oracle Linux 7.
Oracle Linux 6
You can install UEK R3 on Oracle Linux 6 Update 4 or later,
running either the Red Hat compatible kernel or a previous
version of the Unbreakable Enterprise Kernel. If you are
still running an older version of Oracle Linux, first update
your system to the latest available update release.
Starting with Oracle Linux 6 Update 5 for x86-64, UEK R3 is
the default boot kernel for fresh installations of Oracle
Linux 6.
For systems that are currently running a previous version of
the Unbreakable Enterprise Kernel (UEK R2) or the Red Hat
compatible kernel (RHCK), you can switch to UEK R3 at any
time. For details, see:
* Section 3.2, "Switching an Oracle Linux 6 System to UEK
R3 (ULN)"
* Section 3.3, "Switching an Oracle Linux 6 System to UEK
R3 (Public Yum)"
Kernel Source Code
The kernel's source code is available from a public git
source code repository at:
https://oss.oracle.com/git/?p=linux-uek3-3.8.git.
3.1 Upgrading to the Latest UEK Release
For systems that are currently running UEK R3, you upgrade to
the latest UEK release as follows:
1. Ensure the system is configured to receive updates from
the correct channels or repositories.
For Oracle Linux 6, subscribe to either the
ol6_x86_64_UEKR3_latest channel on ULN, or the
ol6_UEKR3_latest repository on the Oracle public yum
server.
For Oracle Linux 7, subscribe to either the
ol7_x86_64_UEKR3 channel on ULN, or the ol7_UEKR3
repository on the Oracle public yum server.
2. Upgrade all packages on the system, including kernel
packages.
# yum update
By default, the boot manager automatically enables the
most recent kernel version so you do not need to change
your GRUB or GRUB 2 configuration.
3. Reboot the system.
Oracle Linux 6:
# shutdown -r now
Oracle Linux 7:
# systemctl reboot
3.2 Switching an Oracle Linux 6 System to UEK R3 (ULN)
If you have a subscription to Oracle Unbreakable Linux
support, you can obtain the packages for Unbreakable
Enterprise Kernel Release 3 (UEK R3) by registering your
system with the Unbreakable Linux Network (ULN) and
subscribing it to additional channels.
Before you begin:
* Ensure the system is registered with ULN.
For information about registering with ULN, see the
Oracle Linux Unbreakable Linux Network User's Guide
(http://docs.oracle.com/cd/E37670_01/E39381/html/index.ht
ml).
* Check that the system meets the requirements for
installing UEK R3.
For details, see Chapter 3, "Installation and
Availability."
* Remove some of the existing OpenFabrics Enterprise
Distribution (OFED) packages.
You only need to do this if you have installed any OFED
packages on your system and you want to replace them with
the latest OFED tools packages. The packages have to be
removed manually, see Section 3.4, "Upgrading OFED
Packages on Oracle Linux 6 Systems."
To Switch a System to UEK R3:
1. Using a browser, log in at http://linux.oracle.com with
the ULN user name and password that you used to register
the system.
2. On the Systems tab, click the link named of your system
in the list of registered machines.
3. On the System Details page, click Manage Subscriptions.
4. On the System Summary page, select each required channel
in the Available Channels list and click the right arrow
to move the channel to the Subscribed Channels list.
The kernel image and user-space packages are available on
the following ULN channels:
Channel Name and Label
Description
Oracle Linux 6 Latest (x86_64)
ol6_x86_64_latest
All packages released for Oracle Linux 6 (x86_64) including
the latest errata packages. (x86_64).
Unbreakable Enterprise Kernel Release 3 for Oracle Linux 6
(x86_64) - Latest
ol6_x86_64_UEKR3_latest
Latest packages for Unbreakable Enterprise Kernel Release 3
for Oracle Linux 6 (x86_64).
Contains the kernel-uek*,
dtrace-modules-*, libdtrace-*, and uname26 packages.
Oracle Linux 6 Dtrace Userspace Tools (x86_64) - Latest
ol6_x86_64_Dtrace_userspace_latest
The latest DTrace userspace tools for Oracle Linux 6
(x86_64).
Contains the dtrace-utils* packages.
OFED supporting tool packages for Unbreakable Enterprise
Kernel on Oracle Linux 6 (x86_64)
ol6_x86_64_ofed_UEK
Latest OpenFabrics Enterprise Distribution (OFED) supporting
tools for the Unbreakable Enterprise Kernel (UEK) on Oracle
Linux 6 (x86_64).
HA Utilities for MySQL and Oracle Linux 6 (x86_64)
ol6_x86_64_mysql-ha-utils
Management Utilities for MySQL HA with Oracle Linux 6.
Contains the drbd84-utils package.
As a minimum, you should subscribe the system to the
ol6_x86_64_latest and the ol6_x86_64_UEKR3_latest
channels. If required, you can also add the channels for
the DTrace, OFED, and DRBD packages.
Caution
Take care not to select the ol6_x86_64_UEK_BETA channel.
Because you are switching to the latest UEK kernel, you
no longer need to subscribe the system to the previous
UEK R2 (ol6_x86_64_UEK_latest) channel.
5. When you have finished selecting channels, click Save
Subscriptions and log out of ULN.
6. Log in as root on the system.
7. Upgrade all packages on the system, including kernel
packages.
# yum update
By default, the boot manager automatically enables the
most recent kernel version so you do not need to change
your GRUB configuration.
8. Reboot the system.
# shutdown -r now
3.3 Switching an Oracle Linux 6 System to UEK R3 (Public Yum)
If your system is not registered with ULN, you can obtain
most of the packages for Unbreakable Enterprise Kernel
Release 3 (UEK R3) from Oracle Public Yum by subscribing it
to additional repositories.
Before you begin:
* Check that the system meets the requirements for
installing UEK R3.
For details, see Chapter 3, "Installation and
Availability."
* Remove some of the existing OpenFabrics Enterprise
Distribution (OFED) packages.
You only need to do this if you have installed any OFED
packages on your system and you want to replace them with
the latest OFED tools packages. The packages have to be
removed manually, see Section 3.4, "Upgrading OFED
Packages on Oracle Linux 6 Systems."
To Switch a System to UEK R3:
1. Log in as root on the system.
2. Change directory to /etc/yum.repos.d.
# cd /etc/yum.repos.d
Note
This assumes that yum on your system is configured to
find repository files in the default /etc/yum.repos.d
directory.
3. Download the Oracle Linux 6 repository configuration
file, http://public-yum.oracle.com/public-yum-ol6.repo.
For example:
# wget http://public-yum.oracle.com/public-yum-ol6.repo
The /etc/yum.repos.d directory is updated with the
repository configuration file.
4. Enable the required repositories by editing the
public-yum-ol6.repo file.
You enable or disable repositories in the file by setting
the value of the enabled directive to 1 or 0 as required.
The kernel image and user-space packages are available on
the following Oracle Public Yum repositories:
Repository
Description
ol6_latest
All packages released for Oracle Linux 6 (x86_64) including
the latest errata packages.
ol6_UEKR3_latest
Latest packages for Unbreakable Enterprise Kernel Release 3
for Oracle Linux 6.
Contains the kernel-uek*, dtrace-modules-*, libdtrace-*, and
uname26 packages.
ol6_ofed_UEK
Latest OpenFabrics Enterprise Distribution (OFED) supporting
tools for the Unbreakable Enterprise Kernel (UEK) on Oracle
Linux 6 (x86_64).
As a minimum, you should enable the ol6_latest and the
ol6_UEKR3_latest repositories.
Note
The DTrace and DRBD utility packages are not available on
Public Yum.
Because you are switching to the latest UEK kernel, you
can disable the previous UEK R2 (ol6_UEK_latest)
repository.
In the following example, the ol6_UEKR3_latest repository
is enabled, and the ol6_UEK_latest repository is
disabled:
[ol6_UEKR3_latest]
name=Latest Unbreakable Enterprise Kernel for Oracle Linux $releasever
($basearch)
baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL6/UEKR3/latest
/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
gpgcheck=1
enabled=1
[ol6_UEK_latest]
name=Latest Unbreakable Enterprise Kernel for Oracle Linux $releasever
($basearch)
baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL6/UEK/latest/$
basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
gpgcheck=1
enabled=0
5. Upgrade all packages on the system, including kernel
packages.
# yum update
By default, the boot manager automatically enables the
most recent kernel version so you do not need to change
your GRUB configuration.
6. Reboot the system.
# shutdown -r now
3.4 Upgrading OFED Packages on Oracle Linux 6 Systems
If you have enabled the ol6_ofed_UEK channel, you must remove
any existing OFED packages for the 32-bit x86 architecture
before you can upgrade the remaining OFED packages on your
system. You must also completely remove and reinstall the
ibutils packages. The latest version of the ibutils package
no longer depends on an ibutils-libs package as the libraries
are now included in ibutils itself.
Use the following command to remove any non-upgradable
packages for the x86 architecture:
# rpm -e infiniband-diags \
libibcm \
libibcm-devel \
libibmad \
libibmad-devel \
libibumad \
libibumad-devel \
libibverbs \
libibverbs-devel \
libmlx4 \
librdmacm \
librdmacm-devel \
opensm-devel \
opensm-libs \
ibacm-devel
Use the following commands to remove the existing ibutils and
ibutils-libs packages and install the new ibutils package:
# rpm -e ibutils ibutils-libs
# yum install ibutils
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