[Ocfs2-users] very slow writes

[Adelino Monteiro]

I've had the same problem in the past and for me using resv_level=0 in
the mount option reduced the problems.
I didn't knew about this mount option but in this page
http://www.mjmwired.net/kernel/Documentation/filesystems/ocfs2.txt
you can find the explanation os this and other options.

Ive reformatted the partition and on all servers I use that option.
This way I've been able to use already 97% of the partitions. We could
go to 100% but I want to have some free space for whatever need that
could arrise.

Hope this helps.

Adelino

On Thu, May 10, 2012 at 10:05 PM, Jay V <jvasaoo at gmail.com> wrote:
> On Thu, May 10, 2012 at 1:59 PM, Jay V <jvasaoo at gmail.com> wrote:
>> Ever since the file system reached 82% full, the file system has gone to a
>> crawl and stalls of only writing up to 10 mb/s, even going as slow as a few
>> kbytes/sec. The file system may be fragmented. Is there a defrag tool?
>>
>> I have tried many options, but nothing seems to work. "data=writeback" does
>> seem to work. We have checked the logs, debugs, traces trying to figure out
>> the probelm, but with no success.
>>
>
> I meant to say data=writeback does not seem to work.
>
>> Features:
>> Compat: backup-super strict-journal-super
>> Incompat: sparse inline-data
>> RO Compat: unwritten
>> debugfs.ocfs2 -R "stats" /dev/drbd2
>>         Revision: 0.90
>>         Mount Count: 0   Max Mount Count: 20
>>         State: 0   Errors: 0
>>         Check Interval: 0   Last Check: Sat Mar 17 05:51:42 2012
>>         Creator OS: 0
>>         Feature Compat: 3 backup-super strict-journal-super
>>         Feature Incompat: 80 sparse inline-data
>>         Tunefs Incomplete: 0
>>         Feature RO compat: 1 unwritten
>>         Root Blknum: 5   System Dir Blknum: 6
>>         First Cluster Group Blknum: 3
>>         Block Size Bits: 12   Cluster Size Bits: 12
>>         Max Node Slots: 2
>>         Extended Attributes Inline Size: 0
>>         Label: imepool2
>>         UUID: 5AAD4275BEBA4F96B8FEE7274FC4D043
>>         Hash: 0 (0x0)
>>         DX Seeds: 0 0 0 (0x00000000 0x00000000 0x00000000)
>>         Cluster stack: classic o2cb
>>         Cluster flags: 0
>>         Inode: 2   Mode: 00   Generation: 2084865048 (0x7c448418)
>>         FS Generation: 2084865048 (0x7c448418)
>>         CRC32: 00000000   ECC: 0000
>>         Type: Unknown   Attr: 0x0   Flags: Valid System Superblock
>>         Dynamic Features: (0x0)
>>         User: 0 (root)   Group: 0 (root)   Size: 0
>>         Links: 0   Clusters: 3496426618
>>         ctime: 0x4aa1e6e7 0x0 -- Fri Sep  4 21:19:51.0 2009
>>         atime: 0x0 0x0 -- Wed Dec 31 16:00:00.0 1969
>>         mtime: 0x4aa1e6e7 0x0 -- Fri Sep  4 21:19:51.0 2009
>>         dtime: 0x0 -- Wed Dec 31 16:00:00 1969
>>         Refcount Block: 0
>>         Last Extblk: 0   Orphan Slot: 0
>>         Sub Alloc Slot: Global   Sub Alloc Bit: 65535
>>
>> Version OCFS2 1.8.0:
>> filename:
>> /lib/modules/2.6.39-100.5.1.el6uek.x86_64/kernel/fs/ocfs2/ocfs2.ko
>> license:        GPL
>> author:         Oracle
>> version:        1.8.0
>> description:    OCFS2 1.8.0
>> srcversion:     A427F5E2A962D0808C8478F
>> depends:        jbd2,ocfs2_stackglue,ocfs2_nodemanager
>> vermagic:       2.6.39-100.5.1.el6uek.x86_64 SMP mod_unload modversions
>> mounted options: rw,_netdev,noatime,nodiratime,heartbeat=local
>>
>> When deleting files it seems to help temporarily. I like to be able to go
>> over 82% without this degradation.
>>
>> I want to minimize downtime as this filesystem is 15TB. Is there a feature I
>> can enable such as "discontig-bg" that will help??
>>
>> Thanks so much for your help!
>> -Jay
>
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-- 
Cumprimentos / Best Regards

Adelino Monteiro