Problems with journal?

Giulio Ferro auryn at zirakzigil.org
Mon Oct 13 20:45:24 UTC 2008


Miroslav Lachman wrote:
> 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.

I'm glad for you. Unfortunately, as I reported in my original message, if
the filesystem is cluttered enough even a simple "find" command can
very nearly freeze the system.
I had jails on the journaled partition, each running a heavily loaded db.

>
> 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.

I believe ZFS is the best thing happened to freebsd in a long time, and
I use it full time in my desktops.
Anyway I deemed it unusable in my production setup, since a 10 times slower
read can't really keep up with that environment. And there is no danger of
reaching disk capacity anytime soon... :-)


More information about the freebsd-geom mailing list