Re: Poor interactive performance with I/O loads with fsync()ing

[Ric Wheeler <rwheeler@redhat.com>]

On 04/11/2010 05:22 PM, Dave Chinner wrote:
> On Sun, Apr 11, 2010 at 08:16:09PM +0200, Thomas Gleixner wrote:
>    
>> On Sun, 11 Apr 2010, Avi Kivity wrote:
>>      
>>> On 04/09/2010 05:56 PM, Ben Gamari wrote:
>>>        
>>>> On Mon, 29 Mar 2010 00:08:58 +0200, Andi Kleen<andi@firstfloor.org>   wrote:
>>>>          
>>>>> Ben Gamari<bgamari.foss@gmail.com>   writes:
>>>>> ext4/XFS/JFS/btrfs should be better in this regard
>>>>>
>>>>>            
>>>> I am using btrfs, so yes, I was expecting things to be better.
>>>> Unfortunately,
>>>> the improvement seems to be non-existent under high IO/fsync load.
>>>>          
>>> btrfs is known to perform poorly under fsync.
>>>        
>> XFS does not do much better. Just moved my VM images back to ext for
>> that reason.
>>      
> Numbers? Workload description? Mount options? I hate it when all I
> hear is "XFS sucked, so I went back to extN" reports without any
> more details - it's hard to improve anything without any details
> of the problems.
>
> Also worth remembering is that XFS defaults to slow-but-safe
> options, but ext3 defaults to fast-and-I-don't-give-a-damn-about-
> data-safety, so there's a world of difference between the
> filesystem defaults....
>
> And FWIW, I run all my VMs on XFS using default mkfs and mount options,
> and I can't say that I've noticed any performance problems at all
> despite hammering the IO subsystems all the time. The only thing
> I've ever done is occasionally run xfs_fsr across permanent qcow2
> VM images to defrag them as the grow slowly over time...
>
> Cheers,
>
> Dave.
>    

And if you are asking for details, the type of storage  you use is also 
quite interesting.

Thanks!

Ric