Date: Mon, 1 Feb 2016 09:25:50 -0500 From: Vick Khera <vivek@khera.org> To: freebsd-questions@freebsd.org Subject: NFS unstable with high load on server Message-ID: <CALd%2BdcfzPU=nMGo41BBZzt3jQnsQJaANVyA222TDM_is2Ueo0A@mail.gmail.com>
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I have a handful of servers at my data center all running FreeBSD 10.2. On one of them I have a copy of the FreeBSD sources shared via NFS. When this server is running a large poudriere run re-building all the ports I need, the clients' NFS mounts become unstable. That is, the clients keep getting read failures. The interactive performance of the NFS server is just fine, however. The local file system is a ZFS mirror. What could be causing NFS to be unstable in this situation? Specifics: Server "lorax" FreeBSD 10.2-RELEASE-p7 kernel locally compiled, with NFS server and ZFS as dynamic kernel modules. 16GB RAM, Xeon 3.1GHz quad processor. The directory /u/lorax1 a ZFS dataset on a mirrored pool, and is NFS exported via the ZFS exports file. I put the FreeBSD sources on this dataset and symlink to /usr/src. Client "bluefish" FreeBSD 10.2-RELEASE-p5 kernel locally compiled, NFS client built in to kernel. 32GB RAM, Xeon 3.1GHz quad processor (basically same hardware but more RAM). The directory /n/lorax1 is NFS mounted from lorax via autofs. The NFS options are "intr,nolockd". /usr/src is symlinked to the sources in that NFS mount. What I observe: [lorax]~% cd /usr/src [lorax]src% svn status [lorax]src% w 9:12AM up 12 days, 19:19, 4 users, load averages: 4.43, 4.45, 3.61 USER TTY FROM LOGIN@ IDLE WHAT vivek pts/0 vick.int.kcilink.com 8:44AM - tmux: client (/tmp/ vivek pts/1 tmux(19747).%0 8:44AM 19 sed y%*+%pp%;s%[^_a vivek pts/2 tmux(19747).%1 8:56AM - w vivek pts/3 tmux(19747).%2 8:56AM - slogin bluefish-prv [lorax]src% pwd /u/lorax1/usr10/src So right now the load average is more than 1 per processor on lorax. I can quite easily run "svn status" on the source directory, and the interactive performance is pretty snappy for editing local files and navigating around the file system. On the client: [bluefish]~% cd /usr/src [bluefish]src% pwd /n/lorax1/usr10/src [bluefish]src% svn status svn: E070008: Can't read directory '/n/lorax1/usr10/src/contrib/sqlite3': Partial results are valid but processing is incomplete [bluefish]src% svn status svn: E070008: Can't read directory '/n/lorax1/usr10/src/lib/libfetch': Partial results are valid but processing is incomplete [bluefish]src% svn status svn: E070008: Can't read directory '/n/lorax1/usr10/src/release/picobsd/tinyware/msg': Partial results are valid but processing is incomplete [bluefish]src% w 9:14AM up 93 days, 23:55, 1 user, load averages: 0.10, 0.15, 0.15 USER TTY FROM LOGIN@ IDLE WHAT vivek pts/0 lorax-prv.kcilink.com 8:56AM - w [bluefish]src% df . Filesystem 1K-blocks Used Avail Capacity Mounted on lorax-prv:/u/lorax1 932845181 6090910 926754271 1% /n/lorax1 What I see is more or less random failures to read the NFS volume. When the server is not so busy running poudriere builds, the client never has any failures. I also observe this kind of failure doing buildworld or installworld on the client when the server is busy -- I get strange random failures reading the files causing the build or install to fail. My workaround is to not do build/installs on client machines when the NFS server is busy doing large jobs like building all packages, but there is definitely something wrong here I'd like to fix. I observe this on all the local NFS clients. I rebooted the server before to try to clear this up but it did not fix it. Any help would be appreciated.help
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