Date: Fri, 26 Jun 2015 19:58:42 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: Gerrit =?utf-8?B?S8O8aG4=?= <gerrit.kuehn@aei.mpg.de> Cc: freebsd-net@freebsd.org, carsten aulbert <carsten.aulbert@aei.mpg.de> Subject: Re: NFS on 10G interface terribly slow Message-ID: <570481533.408618.1435363122433.JavaMail.zimbra@uoguelph.ca> In-Reply-To: <20150626115943.7d0b441cda2c6cc5b817b181@aei.mpg.de> References: <20150625145238.12cf9da3b368ef0b9a30f193@aei.mpg.de> <623856025.328424.1435279751389.JavaMail.zimbra@uoguelph.ca> <20150626115943.7d0b441cda2c6cc5b817b181@aei.mpg.de>
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Gerrit Kuhn wrote: > On Thu, 25 Jun 2015 20:49:11 -0400 (EDT) Rick Macklem > <rmacklem@uoguelph.ca> wrote about Re: NFS on 10G interface terribly slow: > > > RM> Recent commits to stable/10 (not in 10.1) done by Alexander Motin > RM> (mav@) might help w.r.t. write performance (it avoids large writes > RM> doing synchronous writes when the wcommitsize is exceeded). If you can > RM> try stable/10, that might be worth it. > > Ok, I'll schedule an update then, I guess. OTOH, Scott reported that a > similar setup is working fine for him with 10.0 and 10.1, so there is > probably not much to gain. I'll try anyway... > > RM> Otherwise, the main mount option you can try is "wcommitsize", which > RM> you probably want to make larger. > > Hm, which size would you recommend? I cannot find anything about this > setting, not even what the default value would be. Is this reflected in > some sysctl, or how can I find out what the actual value is? > The default (auto tuned) value is reported by "nfsstat -m". It can be set with a mount option (should be something in "man mount_nfs"). If you are doing a test with 1 megabyte writes, I'd set it to at least 1 megabyte. (Basically, writing will be slower for write(2) syscalls that are larger than wcommitsize. After mav@'s patch, the difference isn't nearly as noticable. His other commit makes the auto tuned value more reasonable). If you set it large enough with the "wcommitsize=<N>" mount option, you don't need the updates stable/10. rick > > cu > Gerrit >
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