[ovirt-users] Performance differences between ext4 and XFS

[Fabrice Bacchella]

I just got bitten by this particular problem, on a heavily used disk image. I'm trying to defragment the disk images. Hop this will help.


> Le 8 juin 2017 à 07:19, Markus Stockhausen <stockhausen at collogia.de> a écrit :
> 
> Hi Fernando, 
> 
> we personally like XFS very much. But XFS + qcow2 (even for snapshots in OVirt)
> comes close to a no-go these days. We are experience excessive fragmentation.
> For more info see unresolved Redhat Info:
> 
> https://access.redhat.com/solutions/532663 <https://access.redhat.com/solutions/532663>
> 
> Even with tuning the XFS allocation policy on the qcow2 directory with 
> 
> xfs_io -c 'extsize -R 2M' <qcow2-dir>
> 
> A nice 3rd party explanation can be found here:
> 
> https://blog.codecentric.de/en/2017/04/xfs-possible-memory-allocation-deadlock-kmem_alloc/ <https://blog.codecentric.de/en/2017/04/xfs-possible-memory-allocation-deadlock-kmem_alloc/>
> 
> Markus
> 
> Von: users-bounces at ovirt.org <mailto:users-bounces at ovirt.org> [users-bounces at ovirt.org <mailto:users-bounces at ovirt.org>]" im Auftrag von "FERNANDO FREDIANI [fernando.frediani at upx.com <mailto:fernando.frediani at upx.com>]
> Gesendet: Mittwoch, 7. Juni 2017 23:35
> An: users at ovirt.org <mailto:users at ovirt.org>
> Betreff: [ovirt-users] Performance differences between ext4 and XFS
> 
> Just wanted to find out what filesystem people are using to host Virtual Machines in qcow2 files in a filesystem in Localstorage, ext4 or XFS ?
> 
> I normally like XFS for big files which is the case fo VMs, but wondered if anyone could see any performance advantage when compared with ext4.
> 
> Fernando
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