On Sun, Oct 09, 2011 at 03:56:39AM -0500, Stan Hoeppner wrote: > On 10/8/2011 3:33 PM, Wietse Venema wrote: > > That's a lot of text. How about some hard numbers? > > Maybe not the perfect example, but here's one such high concurrency > synthetic mail server workload comparison showing XFS with a substantial > lead over everything but JFS, in which case the lead is much smaller: > > http://btrfs.boxacle.net/repository/raid/history/History_Mail_server_simulation._num_threads=128.html
Sorry - I don't see unlinks there. Maybe I'm not not reading very carefully... > If anyone has a relatively current (4 years) bare metal "lab" box with > say 24-32 locally attached SAS drives (the more the better) to which I > could get SSH KVM access, have pretty much free reign to destroy > anything on it and build a proper test rig, I'd be happy to do a bunch > of maildir type workload tests of the various Linux filesystems and > publish the results, focusing on getting the XFS+linear concat info into > public view. How many people are running their mail servers on 24-32 SAS spindles verses those running them on two spindles in RAID1? > If not, but if someone with sufficient hardware would like to do this > project him/herself, I'd be glad to assist getting the XFS+linear concat > configured correctly. Unfortunately it's not something one can setup > without already having a somewhat intimate knowledge of the XFS > allocation group architecture. Once performance data is out there, and > there is demand generated, I'll try to publish a how-to. Wow - just what I love doing. Building intimate knowledge of the XFS allocation group architecture to run up a mail server. I'll get right on it. Sarcasm aside - if you ship with stupid-ass defaults, don't be surprised if people say the product isn't a good choice for regular users. > Wietse has called me out on my assertion. The XFS allocation group > design properly combined with a linear concat dictates the performance > is greater for this workload, simply based on the IO math vs striped > RAID. All those who have stated they use it testify to the increased > performance. But no one has published competitive analysis yet. I'd > love to get such data published as it's a great solution and many could > benefit from it, at least Linux users anyway--XFS is only available on > Linux now that IRIX is dead... I tried XFS for our workload (RAID1 sets, massive set of unlinks once per week when we do the weekly expunge cleanup) - and the unlinks were just so nasty that we decided not to use it. I was really hoping for btrfs to be ready for prime-time by now, but that's looking unlikely to happen any time soon. Maybe my tuning fu was bad - but you know what, I did a bit of reading and chose options that provided similar consistency guarantees to the options we were currently using with reiserfs. Besides, 2.6.17 was still recent memory at the time, and it didn't encourage me much. Bron.
