Oracle® Linux
Release Notes for Unbreakable Enterprise Kernel Release 3 Quarterly
Update 2
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E52507-01
May 2014
Abstract
This document contains information on Quarterly Update 2 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. Oracle recommends
that you read this document before installing or upgrading the
Unbreakable Enterprise Kernel Release 3.
Document generated on: 2014-05-19 (revision: 1876)
_______________________________________________________
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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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/documentati
on/index.html.
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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 on the x86-64 architecture. It is
based on the mainline Linux kernel version 3.8.13.
The 3.8.13-35 release is the second 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
* Updates to the hpsa driver adds the HP SSD Smart Path feature,
which improves the performance of select HP Smart Array Controllers
in SSD-based HP ProLiant servers.
* Support has been added for the Intel Ethernet Controller XL710
family.
* Paravirtualization drivers have been added or updated to
support Oracle Linux guests running on Microsoft Hyper-V.
* The DTrace profile provider now supports profile-n probes that
fire at a fixed interval at high-interrupt level on all active
CPUs. (For comparison, tick-n probes fire on only one CPU per
interval and the CPU on which they fire can change over time.)
The units of n default to a frequency expressed as a rate of
firing per second. You can use the same suffixes as for tick-n
probes to specify either a time interval or a frequency.
* Quarterly Update 2 includes a change to requirements for
dracut, version 004-303.0.3 or higher is now required.
* The kernel-uek-headers package is no longer built and
delivered with UEK3 releases. In order to build kernel
modules, you only need the kernel-uek-devel package. If you
need a headers package, use the kernel-headers package.
* Limited support for client-side NFS over RDMA (Remote Direct
Memory Access) has been enabled. Server-side NFS over RDMA is
not enabled.
1.2 Xen Improvements
* Fixes in netback for Rx (receive) and Tx (transmit) path
issues (Bug ID 18379272).
* Fixes in netfront for resources leaks and missed timer (Bug ID
18348558).
* Fixes in virtual CPU (VCPU) hotplug code (Bug ID 18348666).
* Fixes in physical to machine (P2M) code for PCI passthrough
(Bug ID 18355746).
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 (FCoE) driver
(bnx2fc) updated to 2.4.2e.
Brocade
* Fibre Channel host bus adapter (HBA) driver fcpim (bfa)
updated to 3.2.23.0.
Cisco
* Cisco FCoE HBA driver (fnic) updated to 1.6.0.10.
Emulex
* OneConnect (previously known as Blade Engine 2) Open-iSCSI
driver (be2iscsi) updated to 10.2.125.0o.
HP
* HP Smart Array Controller driver (hpsa) updated to 3.4.4-1.
Intel
* NVM Express device driver (nvme) updated to 0.9.
QLogic
* Fibre Channel HBA driver (qla2xxx) updated to
8.07.00.08.39.0-k1.
* iSCSI HBA driver (qla4xxx) updated to 5.04.00.05.06.02-uek3.
1.3.2 Network Adapter Drivers
Broadcom
* NetXtreme II 1 Gigabit network adapter driver (bnx2) updated
to 2.2.5f.
* NetXtreme II 10 Gigabit network adapter driver (bnx2x) updated
to 1.710.10.
* NetXtreme II Converged Network Interface Card core driver
(cnic) updated to 2.5.18d.
* Tigon3 ethernet adapter driver (tg3) updated to 3.136e.
Brocade
* 10 Gigabit PCI Express network adapter driver (bna) updated to
3.2.23.0.
Cisco
* VIC Ethernet NIC Driver (enic) updated to 2.1.1.50.
Emulex
* OneConnect (previously known as Blade Engine 2) 10Gbps adapter
driver (be2net) updated to 10.2u.
Intel
* PRO/1000 PCI Express Gigabit network adapter driver (e1000e)
updated to 3.0.4-NAPI.
* Ethernet Connection XL710 network adapter driver (i40e)
version 0.3.9-k added.
* Gigabit Ethernet network adapter driver (igb) updated to
5.1.2.
* Gigabit Virtual Function driver (igbvf) updated to 2.3.3.
* 10 Gigabit PCI Express network adapter driver (ixgbe) updated
to 3.19.1.
* 10 Gigabit PCI Express Virtual Function driver (ixgbevf)
updated to 2.12.1.
Oracle
* Sun Blade 40/10Gigabit Ethernet network driver (sxge) updated
to 0.11202013.
* Sun Blade Virtualized 40/10Gigabit Ethernet network driver
(sxgevf) updated to 0.11202013.
QLogic
* 1/10 GbE Converged/Intelligent Ethernet adapter driver
(qlcnic) updated to 5.3.55.6.
* 10 Gigabit PCI-E Ethernet adapter driver (qlge) updated to
1.00.00.34.
1.3.3 Miscellaneous Drivers
Intel
* Package Level C-state Idle Injection for Intel CPUs driver
(intel_powerclamp) added.
Microsoft
* The following paravirtualization drivers have been added or
updated to support Oracle Linux guests running on Microsoft
Hyper-V:
+ HID-compliant mouse driver (hid-hyperv)
+ Balloon driver (hv_balloon)
+ Network driver (hv_netvsc)
+ Virtual storage driver (hv_storvsc)
+ Utilities (hv_utils)
+ VMBus driver (hv_vmbus)
+ Synthetic video frame buffer driver (hyperv_fb)
+ Keyboard driver (hyperv-keyboard)
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/.
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.
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.
btrfs
* The btrfs device scan command no longer displays an error
message if devices on which you create btrfs file systems are
subsequently reused in another file system. (Bug ID 17087097)
* Fixes have been applied to the btrfs-convert and mkfs.btrfs -r
commands to prevent the creation of btrfs file systems on
devices that are already mounted. (Bug ID 18061751, 18606274)
* The bug that can cause data corruption when reading or
updating compressed extents has been fixed. (Bug ID 18403731)
* In order to alleviate problems with defragmentation,
snapshot-aware defragmentation has been disabled. (Bug ID
18348652)
* Users can now only create snapshots of subvolumes that they
own. Previously it was possible for users to create a snapshot
of any subvolume. (Bug ID 18348620)
DTrace
* Problems with symbol lookup when using ustack() with
multithreaded processes, which could cause threads to lock up,
have been fixed. It also ensures that DTrace assigns the
correct values to the pid and ppid variables. (Bug ID
18412802)
* Added support for profile-n probes to the DTrace profile
provider. (Bug ID 18323501, 18323513)
* The output from the stack() action has been corrected.
Previously, this could include incorrect addresses, in
particular for kernel functions that allocate data structures
on the stack. (Bug ID 18323450)
* Interrupting DTrace with a SIGINT while monitored processes
are dying no longer hangs DTrace on a condition variable. (Bug
ID 18689795)
* Symbol lookups on processes that died at the same instant now
always fail and no longer access freed memory. (Bug ID
18550863)
* Killing DTrace while a ustack() is in progress no longer risks
killing crucial system daemons. (Bug ID 18600515)
iSCSI
* Previously when a system performed a scan for LUNs on a
storage appliance (typically a Sun ZFS Storage Appliance) and
the storage appliance reports a LUN as not ready or
unavailable, the scan was aborted. This has been fixed, and
systems now continue to scan for the available LUNs. (Bug ID
18271070)
* The issue where the kernel reports connection error 1020
during an iSCSI session logout has been fixed. (Bug ID
17585443)
Message Queue
* A fix has been applied to correct the msgrcv() functionality
so that, when a negative msgtyp is specified, the first
message of the lowest type that is less than or equal to the
absolute value of msgtyp is received. (Bug ID 18348614)
OCFS2
* A fix has been applied to the OCFS2 recovery process that
could cause the whole OCFS2 cluster to hang. (Bug ID 18285345)
SELinux
* The bug that enabled a empty (zero-length) security context to
be set has been fixed. (Bug ID 18348651)
Virtualization
* Fix applied to support the live migration of hardware
virtualized machine (HVM) guests that have more than 32
virtual CPUs. (Bug ID 18552664)
* The fix has been applied for xen XSA-90 Linux netback crash
trying to disable due to malformed packet. (Bug ID 18528832)
* If a guest is configured with 256 virtual CPUs, the shutdown
of the guest appears to hang but does eventually complete.
(Bug ID 18380043)
2.2 Known Issues
This section describes the known issues in this update.
ACPI
* On some systems you might see ACPI-related error messages in
dmesg similar to the following:
ACPI Error: [CDW1] Namespace lookup failure, AE_NOT_FOUND
ACPI Error: Method parse/execution failed [_SB_._OSC||\||]
ACPI Error: Field [CDW3] at 96 exceeds Buffer [NULL] size 64 (bits)]]
>
These messages, which are not fatal, are caused by bugs in the
BIOS. Contact your system vendor for a BIOS update. (Bug ID
13100702)
* 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-cp
ufreq instead.
modprobe: FATAL: Error inserting acpi_cpufreq
There is no known workaround for this error. (Bug ID 17034535)
ASM
Calling the oracleasm init script, /etc/init.d/oracleasm, with the
parameter scandisks can lead to error messages about missing
devices similar to the following:
oracleasm-read-label: Unable to open device "device": No such file or
directory
However, the device actually exists. You can ignore this error
message, which is triggered by a timing issue. Only use the init
script to start and stop the oracleasm service. All other options,
such as scandisks, listdisk, and createdisk, are deprecated. For
these and other administrative tasks, use /usr/sbin/oracleasm
instead. (Bug ID 13639337)
bnx2x Driver
When using the bnx2x driver in a bridge, disable Transparent
Packet Aggregation (TPA) by including the statement options bnx2x
disable_tpa=1 in /etc/modprobe.conf. (Bug ID 14626070)
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.
* 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. (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)
* The btrfs subvolume delete command may result in a "Directory
not empty" error. This error message is incorrect. The actual
reason that the subvolume cannot be deleted is that the
subvolume is configured as the default subvolume. The default
subvolume is the subvolume that is mounted when no subvolume
is specified with the mount command. Before you can delete the
subvolume, you need to configure a different default subvolume
using the btrfs subvolume set-default command. (Bug ID
17661944)
* 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.
CPU Microcode Update Failures on PVM or PVHVM Guests
When running Oracle Linux 6 with UEK R3, you might see error
messages in dmesg or /var/log/messages similar to this one:
microcode: CPU0 update to revision 0x6b failed.
You can ignore this warning. You do not need to upgrade the
microcode for virtual CPUs as presented to the guest. (Bug ID
12576264, 13782843)
DHCP Lease is not Obtained at Boot Time
If DHCP lease negotiation takes more than 5 seconds at boot time,
the following message is displayed:
ethX: failed. No link present. Check cable?
If the ethtool ethX command confirms that the interface is
present, edit /etc/sysconfig/network-scripts/ifcfg-ethX and set
LINKDELAY=N, where N is a value greater than 5 seconds (for
example, 30 seconds). Alternatively, use NetworkManager to
configure the interface. (Bug ID 16620177)
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 fun
ction 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)
* The intensive direct random writing to files opened for
synchronous I/O (O_DIRECT, O_SYNC) with unwritten extent
conversions may hang in some circumstances. (Bug ID 18389351)
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
source:
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)
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 correct operation of containers might require that you
completely disable SELinux on the host system. For example,
SELinux can interfere with container operation under the
following conditions:
+ Running the halt or shutdown command from inside the
container hangs the container or results in a permission
denied error. (An alternate workaround is to use the init
0 command from inside the container to shut it down.)
+ Setting a password inside the container results in a
permission denied error, even when run as root.
+ You want to allow ssh logins to the container.
To disable SELinux on the host:
1. Edit the configuration file for SELinux,
/etc/selinux/config and set the value of the SELINUX
directive to disabled.
2. Shut down and reboot the host system.
* 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/toc.ht
m#BHCCADGD). (Bug ID 17217854)
NUMA Warning Messages on a Non-NUMA System
You can safely ignore the following warning messages in dmesg and
/var/log messages if you see them on a non-NUMA system:
kernel: NUMA: Warning: node ids are out of bound, from=-1 to=-1 dista
nce=10
hcid[4293]: Register path:/org/bluez fallback:1
kernel: No NUMA configuration found
(Bug ID 13711370)
Power/Level is Deprecated Message (libfprint)
The following message might appear in dmesg or /var/log/messages:
WARNING! power/level is deprecated; use power/control instead.
The USB subsystem in UEK R3 deprecates the power/level sysfs
attribute in favor of the power/control attribute. The libfprint
fingerprinting library triggers this warning via udev rules that
try to use the old attribute first. You can safely ignore this
warning. The setting of the appropriate power level still
succeeds. (Bug ID 13523418)
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/sp.htm
l#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
This release removes the Transparent Huge Pages (THP) feature.
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. 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)
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)
Chapter 3 Installation and Availability
You can install Unbreakable Enterprise Kernel Release 3 (UEK R3)
on Oracle Linux 6 Update 4 or newer, 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.
UEK R3 is supported on the x86-64 architecture but not on x86.
The kernel's source code is available via a public git source code
repository at:
https://oss.oracle.com/git/?p=linux-uek3-3.8.git.
Starting with Oracle Linux 6 Update 5 for x86-64, UEK R3 is the
default boot kernel for fresh installations of Oracle Linux.
For systems that are running UEK R3 and are subscribed to the
ol6_x86_64_UEKR3_latest channel on ULN, or the ol6_UEKR3_latest
repository in the Oracle Public Yum repository, you upgrade to the
latest UEK release as follows:
1. 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.
2. Reboot the system.
# shutdown -r now
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 3.1, "Switching a System to UEK R3 (ULN)"
* Section 3.2, "Switching a System to UEK R3 (Public Yum)"
3.1 Switching a 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.html).
* 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 3.3, "Upgrading OFED Packages."
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
3.2 Switching a 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 3.3, "Upgrading OFED Packages."
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 utility and DRBD 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 $releaseve
r ($basearch)
baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL6/UEKR3/lates
t/$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 $releaseve
r ($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
3.3 Upgrading OFED Packages
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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