On Tue, Jan 12, 2016 at 10:45 PM, Markus Stockhausen < stockhau...@collogia.de> wrote:
> >> Von: Yaniv Kaul [yk...@redhat.com] > >> Gesendet: Dienstag, 12. Januar 2016 13:15 > >> An: Markus Stockhausen > >> Cc: users@ovirt.org; Mike Hildebrandt > >> Betreff: Re: [ovirt-users] NFS IO timeout configuration > >> > >> On Tue, Jan 12, 2016 at 9:32 AM, Markus Stockhausen > stockhau...@collogia.de> wrote: > >> Hi there, > >> > >> we got a nasty situation yesterday in our OVirt 3.5.6 environment. > >> We ran a LSM that failed during the cleanup operation. To be precise > >> when the process deleted an image on the source NFS storage. > > > > Can you share with us your NFS server details? > >Is the NFS connection healthy (can be seen with nfsstat) > >Generally, delete on NFS should be a pretty quick operation. > > Y. > > Hi Yaniv, > > we usually have no problems with our NFS server. From our observations we > only have issues when deleting files with many extents. This applies to all > OVirt images files. Several of them have more than 50.000 extents, a few > even more than 300.000. > > > xfs_bmap 1cb5906f-65d8-4174-99b1-74f5b3cbc537 > ... > 52976: [629122144..629130335]: 10986198592..10986206783 > 52977: [629130336..629130343]: 10986403456..10986403463 > 52978: [629130344..629138535]: 10986206792..10986214983 > 52979: [629138536..629138543]: 10986411656..10986411663 > 52980: [629138544..629145471]: 10986214992..10986221919 > 52981: [629145472..629145575]: 10809903560..10809903663 > 52982: [629145576..629145599]: 10737615056..10737615079 > > Our XFS is mounted with: > > /dev/mapper/vg00-lvdata on /var/nas4 type xfs > (rw,noatime,nodiratime,allocsize=16m) > > Why we use allocsize=16M? We once started with allocize=512MB. This > led to sparse files that did not save much bytes. Because a single byte > written > resulted in a 512MB allocation. Thin allocation of these files resulted in > long runtimes > for formatting disks inside the VMS. So we reduced to 16MB as a balanced > config > > This works quite well but not for remove operations. > > Better ideas? > Sounds like an XFS issue more than NFS. I've consulted with one of our XFS gurus - here's his reply: For vm image files, users should set up extent size hints to define > the minimum extent allocation size in a file - allocsize does > nothing for random writes into sparse files. I typically use a hint > of 1MB for all my vm images....` > Y. > > Markus > > > >
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