On 8/25/15 3:32 PM, Shrinand Javadekar wrote: > Hi, > > I have 23 disks formatted with XFS on a single server. The workload is > Openstack Swift. See this email from a few months ago about the > details: > > http://oss.sgi.com/archives/xfs/2015-06/msg00108.html > > I am observing some strange behavior and would like to get some > feedback about why this is happening. > > I formatted the disks with xfs (mkfs.xfs) and deployed Openstack Swift > on it. Writing 100GB of data into Swift in batches of 20GB each gave > us the following throughput: > > 20 GB: 93MB/s > 40 GB: 65MB/s > 60 GB: 52MB/s > 80 GB: 50MB/s > 100 GB: 48MB/s > > I then re-formatted the disks with mkfs.xfs -f and ran the experiment > again. This time I got the following throughput: > > 20 GB: 118MB/s > 40 GB: 95MB/s > 60 GB: 74MB/s > 80 GB: 68MB/s > 100 GB: 63MB/s > > I've seen similar results twice. How did you do the above twice, out of curiosity? If it's the same set of disks, the 3rd mkfs would require "-f" to overwrite the old format. > Any ideas why this might be happening? With the paucity of information you've provided, nope! What version of xfsprogs are you using? What was the output of mkfs.xfs each time; did the geometry differ? -f sets force_overwrite, which only does 3 things: 1) overwrite existing filesystem signatures 3) zeros out old xfs structures on disk 2) allow mkfs to proceed on a misaligned device I don't see why any of those behaviors would change runtime behavior. Maybe you have other variables in your performance testing, and two tests isn't enough to sort out noise? -Eric > Thanks in advance. > -Shri > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
