On Fri, 2011-06-03 at 09:29 +0200, Vladimir Elisseev wrote: > Hello, > > After using nfs3 with kerberos for a while I discovered very poor > performance for some file operations like creation of files. There are > two observations: > - the overal nfs3 performance is good: for instance copying large files > works fine > - this poor performance is definitely related to kerberos as the same > volume exported without sec=krb5 works ~10 times faster with creating > files > I'd appreciate if somebody can explain this behaviour? > > Below are some details about NFS server and client: > server: > - kernel 2.6.36 > - export options rw,sec=krb5,no_root_squash,no_subtree_check > - nfs-utils 1.2.3 > > client: > - kernel 2.6.38 or 2.6.39 > - mout options (from /proc/mounts): > rw,nosuid,nodev,noatime,vers=3,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5,mountaddr=192.168.1.219,mountvers=3,mountport=32767,mountproto=tcp,local_lock=none,addr=192.168.1.219 > > when the same volume exported without sec=krb5, the only option changes > in /proc/mounts is sec=sys Can you please tell us a bit more about how you are measuring this? I might expect a x10 performance difference if the workload is dominated by the actual setting up of the RPCSEC_GSS session (i.e. you are timing mount+create one file or something like that). If we're talking about a workload where the RPCSEC_GSS negotiation can be neglected, however (mount+create 100000 files), I wouldn't expect any measurable performance impact from 'sec=krb'. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
