Problems with journal?

Miroslav Lachman 000.fbsd at quip.cz
Sun Oct 12 16:54:21 UTC 2008


Giulio Ferro wrote:
> Giulio Ferro wrote:
> 
>> I'm experiencing very serious delay issues in 2 production servers.
> 
> [...]
> 
>>
>> I hope any of you can help me look in the right direction, and point 
>> me to any further tests to try or tunable
>> to set...
>>
>> Thanks in advance.
>>
> 
> I didn't receive any answer to this, so I'm guessing ufs journal
> is abandoned or there is no interest in supporting it in production
> environment.
> Anyway I removed it from my servers and reverted to standard UFS,
> so the problems disappeared.  I also tried zfs (the only other journaled
> filesystem available on freebsd). I didn't experiences the hanging behavior
> I did with journaled ufs, but it's considerably slower than standard ufs
> (1/2 slower writes, 1/10 slower reads)...

I am using gjournal on few production machines (not heavily IO loaded) 
without any hangs.
Form time to time I get this message in log:

fsync: giving up on dirty
0xc553e880: tag devfs, type VCHR
     usecount 1, writecount 0, refcount 5305 mountedhere 0xc54a1c00
     flags ()
     v_object 0xc5526e88 ref 0 pages 33571
      lock type devfs: EXCL (count 1) by thread 0xc52aaa50 (pid 41)
	dev da0s2e.journal
GEOM_JOURNAL: Cannot suspend file system /vol0 (error=35).

I asked this message in the list 6 month ago and Eric Anderson wrote 
that it shouldn't be a problem.

I tested ZFS and UFS comparing speed of copying ports tree in 
incremental endless loop - UFS became slower and slower with more used 
inodes, but ZFS had same speed even on almost full partition. At the end 
of the test, ZFS was about three times faster than UFS+SU.

Miroslav Lachman


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