Hi. I somewhat mitigated the problem by mount option timeo=10, but this issue still heavily affects NFS throughput. So yes, I'm willing to test, just have to find some free time to do it. I will report as soon as I get results. Thanks for reply, I thought my message was lost forever :) On Tue, 21 Aug 2012 13:43:55 -0400 "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote: > Are you still willing to test patches? If so, this would be worth a > try: > > http://marc.info/?l=linux-nfs&m=134550227125610&w=2 > > >From a quick look at your logs it looks likely to address the same > problem. > > Apologies for the delayed response, we finally just happened to get the > clue necessary to make the problem obvious.... > > --b. > > On Tue, May 08, 2012 at 02:44:19AM +0400, parafin wrote: > > Hello. > > I'm having a problem with my NFS share. It's been present for some time > > now, kernel versions got upgraded, setup has been changed, but since I > > can't remember for sure when it started, I'll just describe my current > > configuration. But first the problem itself. > > Periodically (I would say every GB of data or so) reads from NFS share > > hang during which nfsd kernel thread on server eats CPU but no data > > gets sent to the client. After a minute everything comes to norm again > > (no action on my part is required). First thing I did to debug this is > > I enabled verbose output in all userspace daemons both on client and > > server - it produced no output whatsoever during the problematic period > > of time. Next I dumped network traffic on TCP port 2049 both on client > > and server - there was no packet drops or any other strange stuff, > > except that client restarted the TCP connection to 2049 port after a > > minute of silence from server (which resulted in data flowing again). > > This was confirmed by kernel debug output from client (echo 65535 | tee > > nfs_debug nfsd_debug nlm_debug rpc_debug) - NFS client sent a server > > READ request with 60 seconds timeout, timeout was reached and resulted > > in dropping and restarting of NFS TCP connection. So this points to NFS > > server kernel code. Kernel debug output on server is quite large and > > spikes during the hangs - I've attached deduplicated (by hand) version > > of it to this email. I couldn't find anything strange in there, but I > > don't understand most of it anyway. > > My current setup - both server and client are Linux 3.3.3, NFSv4 with > > sec=krb5, it runs through local network 192.168.0.0/24 with no > > firewalls (client has iptables disabled in kernel, server ACCEPTs > > everything from internal interface). Client uses Wi-Fi, server - > > Ethernet with VLANs, so traffic goes through AP. But since network dumps > > on server and client are the same, network configuration IMHO is > > irrelevant, I just added it for fullness of description. Most common > > usage (and test case) of this NFS share is watching some videos using > > mplayer. Underlying filesystem is XFS (though ext4 is used for other > > shares on the same server). > > I'm ready to provide additional information or test some patches, since > > this problem is quite annoying (and IMHO got worse with time). > > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
