Slower performance with ext4
Mark Kirkwood
markir at paradise.net.nz
Mon Nov 2 07:30:40 UTC 2009
Mark Kirkwood wrote:
> Christopher Chan wrote:
>
>> Heh, what do you know? I have been burned by XFS after a powerloss and
>> got over 4000 zero length files in a postfix queue. No filesystem
>> corruption, just zero data files. You want to tell me that postfix does
>> not use fsync? You can guess what I did to the XFS filesystem mounted
>> for the queue directory. I destroyed it and got ext3 instead in full
>> data journal mode. Which I repeated on all the other mtas that had a XFS
>> filesystem for their mail queue.
>>
>>
>>
>
> Hmm - not gonna get into trading personal insults , as nothing is to be
> gained that way.
>
> You were running this on server grade hardware? or - let me guess - a
> workstation with cheap sata drives? I have run many instances of mysql,
> postgres and oracle on *server* grade hardware [1] with xfs for probably
> the last 7 years and never have *any* data corruption issue in spite of
> many power outages...
>
> regards
>
> Mark
>
> [1] meaning a designated server mobo with eec ram and scsi (or sas) hard
> drives.
>
>
>
Interesting data point for both of us:
http://blogs.gnome.org/alexl/2009/03/16/ext4-vs-fsync-my-take/
He claims ext4 is safe with sensible usage of fsync but reckons xfs is
not. Without wading through the code for the various fs it is tricky to
be 100% sure if he is correct or mistaken, as it is clearly *possible*
for the respective fs drivers to intercept the f(data)sync etc calls and
do undeserved violence to 'em....
regards
Mark
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