使用nfsstat -c,我看到一个高“authrefrsh”(在某些系统上称为“newcred”)依赖于我的NFS客户端pc上的ls等操作,并查找包含~1000个文件的目录.这与性能非常差(20分钟目录列表)相关.缓存的NFS操作不会出现此行为(authrefrsh或减速).
每次检查nfsstat时,authrefrsh =调用：
$nfsstat -c Client rpc stats: calls retrans authrefrsh 280462 0 280462 Client nfs v3: null getattr setattr lookup access readlink 0 0% 126990 45% 0 0% 10062 3% 58592 20% 0 0% read write create mkdir symlink mknod 25030 8% 0 0% 65 0% 0 0% 2 0% 0 0% remove rmdir rename link readdir readdirplus 0 0% 0 0% 0 0% 0 0% 0 0% 59654 21% fsstat fsinfo pathconf commit 0 0% 20 0% 10 0% 0 0%
连接细节：
$mount.nfs -v nfshost:/share/dir /somedir mount.nfs: timeout set for Tue Feb 21 18:12:18 2012 mount.nfs: trying text-based options 'vers=4,addr=192.168.xx.xx,clientaddr=192.168.xx.xx' mount.nfs: mount(2): Operation not permitted mount.nfs: trying text-based options 'addr=192.168.xx.xx' mount.nfs: prog 100003,trying vers=3,prot=6 mount.nfs: trying 192.168.xx.xx prog 100003 vers 3 prot TCP port 2049 mount.nfs: prog 100005,prot=17 mount.nfs: trying 192.168.xx.xx prog 100005 vers 3 prot UDP port 1011 nfshost:/share/dir on /somedir type nfs
nfshost RPC环境：
$rpcinfo -T udp nfshost nfs program 100003 version 2 ready and waiting program 100003 version 3 ready and waiting program 100003 version 4 ready and waiting $rpcinfo -T udp nfshost mountd program 100005 version 1 ready and waiting program 100005 version 2 ready and waiting program 100005 version 3 ready and waiting $rpcinfo -T udp nfshost nlockmgr program 100021 version 1 ready and waiting rpcinfo: RPC: Program/version mismatch; low version = 1,high version = 4 program 100021 version 2 is not available program 100021 version 3 ready and waiting program 100021 version 4 ready and waiting $rpcinfo -T udp nfshost llockmgr rpcinfo: RPC: Program not registered $rpcinfo nfshost program version netid address service owner 100000 2 tcp 0.0.0.0.0.111 portmapper unknown 100000 2 udp 0.0.0.0.0.111 portmapper unknown 100024 1 udp 0.0.0.0.2.212 status unknown 100024 1 tcp 0.0.0.0.2.215 status unknown 100021 1 udp 0.0.0.0.226.67 nlockmgr unknown 100021 3 udp 0.0.0.0.226.67 nlockmgr unknown 100021 4 udp 0.0.0.0.226.67 nlockmgr unknown 100021 1 tcp 0.0.0.0.134.55 nlockmgr unknown 100021 3 tcp 0.0.0.0.134.55 nlockmgr unknown 100021 4 tcp 0.0.0.0.134.55 nlockmgr unknown 100011 1 udp 0.0.0.0.3.230 rquotad unknown 100011 2 udp 0.0.0.0.3.230 rquotad unknown 100011 1 tcp 0.0.0.0.3.233 rquotad unknown 100011 2 tcp 0.0.0.0.3.233 rquotad unknown 100003 2 udp 0.0.0.0.8.1 nfs unknown 100003 3 udp 0.0.0.0.8.1 nfs unknown 100003 4 udp 0.0.0.0.8.1 nfs unknown 100003 2 tcp 0.0.0.0.8.1 nfs unknown 100003 3 tcp 0.0.0.0.8.1 nfs unknown 100003 4 tcp 0.0.0.0.8.1 nfs unknown 100005 1 udp 0.0.0.0.3.243 mountd unknown 100005 1 tcp 0.0.0.0.3.246 mountd unknown 100005 2 udp 0.0.0.0.3.243 mountd unknown 100005 2 tcp 0.0.0.0.3.246 mountd unknown 100005 3 udp 0.0.0.0.3.243 mountd unknown 100005 3 tcp 0.0.0.0.3.246 mountd unknown
环境：
$uname -a Linux whiteheat 3.0.0-15-generic #26-Ubuntu SMP Fri Jan 20 17:23:00 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux $mount.nfs a b -V mount.nfs: (linux nfs-utils 1.2.4)
解决方法
我在NFS中遇到了这个问题.在我的情况下问题是由于actimeo设置得太低.虽然您可能没有使用这个确切的设置,但有一整套设置可能会造成严重破坏：acregmin,acregmax,acdirmin和acdirmax.基本上发生的是系统从NFS缓存文件属性.这些设置会影响从NFS刷新之前保留文件属性的时间.在使用频繁的系统上,这些刷新变得非常明显.
另一个有问题的设置是noac.如果您使用此功能,则可以保证所有其他客户端都可以立即使用任何写入操作.但是,写入将等到完成写入远程而不是使用后写.如果频繁写入NFS,这可能会使系统陷入困境.
This是一篇有趣的博客文章,他们讨论了不同的选项及其对NFS性能的影响.您还可以查看NFS的man页面以获取更多指导.不幸的是,authrefrsh可能有点像红鲱鱼,我的问题可能完全无关,尽管有类似的症状.
