On 07/04/2012 11:58 AM, Alexandre DERUMIER wrote:
Hi, I see same messages here after upgrade to 0.48.
with random write benchmark.
I have more lags than before with 0.47 (but disks are at 100% usage, so can't tell if it's normal or not)
----- Mail original -----
De: "David Blundell"<David.Blundell@xxxxxxxxxxxxxxxx>
À: ceph-devel@xxxxxxxxxxxxxxx
Envoyé: Mercredi 4 Juillet 2012 18:53:02
Objet: Slow request warnings on 0.48
I have three servers running mon and osd using Ubuntu 12.04 that I have been testing with RADOS storing RBD KVM instances
0.47.3 worked extremely well (once I got over a few btrfs issues). The same servers running 0.48 give a large number of "[WRN] slow request" messages whenever I generate a lot of random IO in the KVM instances using iozone. The slow responses eventually leads to disk timeouts on the KVM instances.
I have erased the osds and recreated on new btrfs volumes with the same result.
I have also tried switching to xfs using mkfs.xfs -n size=64k with noatime, inode64,delaylog,logbufs=8,logbsize=256k
Xfs gives the same result - the iozone tests run fine until the random IO starts and then there are lots of slow request warnings.
Does anyone have any ideas about the best place to start troubleshooting / debugging?
Thanks,
David
Hi David and Alexandre,
Does this only happen with random writes or also sequential writes? If
it happens with sequential writes as well, does it happen with rados bench?
--
Mark Nelson
Performance Engineer
Inktank
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