Hi, On Sun, 2009-11-08 at 14:41 +0200, Samuli Heinonen wrote: > Hello, > > I'm testing AoE as Xen storage backend. On my other machines I have CentOS > installed and I'd like to use it also as Xen Dom0. Main goal is to use > CLVM on top of AoE and share each DomU an own LVM slice. > > However, the performance isn't that good from CentOS clients. With AoE > module delivered with CentOS write speed is around 15-20 MB/s and with > driver version 73 write speed is around 30-40 MB/s and read speed is close > to 100 MB/s. When doing write tests I see lots of error and retransmit > messages in /dev/etherd/err file. Also I/O wait grows pretty high on AoE > target when writing. Weird thing is that when using Opensuse 11.1 as > client on exactly same machine write speed is also near to 100 MB/s and at > least I haven't noticed anything special on I/O wait or loads. > > On target I have CentOS 5.4 running with kernel 2.6.18-164.6.1 and on > client I have tried with exactly same CentOS version and Opensuse 11.1 > with kernel 2.6.27. Both client and target machine has 4 GB RAM. Target > has SysKonnect SK-9E21D NIC and client has HP NC110T. Both ends have MTU > set to 9000. Currently I have direct link set between them for testing > purposes. I have also tested with optimizations mentioned at > http://xenaoe.org/Virtualization/wiki/AoEOptimizations but they doesn't > seem to make any diffrence. > > Is there anything I could do or any explanations why performance is poor > on CentOS?
It would be helpful if you could provide some more information about your setup. Answers to the following questions would be a good start: What kind of switch is being used for the storage back end? Does each server have a GB nic used exclusively for storage? Are jumbo frames enabled on the nics and the switch? Did you do any sysctl tweaks to adjust rx/tx buffers to be more in line with jumbo frames? Finally, what are you using on the storage node for a target? vblade, kvblade .. or one of the other multi threading user space implementations? Hunting down that kind of bottle neck will be easier after you share that information. Cheers, --Tim Monkey + Typewriter = Echoreply ( http://echoreply.us ) ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Aoetools-discuss mailing list Aoetools-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/aoetools-discuss
