Slower performance with ext4

[Mark Kirkwood]

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