Hi, currently I'm trying to debug a very strange phenomenon on a nearly full pool (96%). Here are the symptoms: over NFS, a find on the pool takes a very long time, up to 30s (!) for each file. Locally, the performance is quite normal. What I found out so far: It seems that every nfs write (rfs3_write) blocks until the txg is flushed. This means a write takes up to 30 seconds. During this time, the nfs calls block, occupying all NFS server threads. With all server threads blocked, all other OPs (LOOKUP, GETATTR, ...) have to wait until the writes finish, bringing the performance of the server effectively down to zero. It may be that the trigger for this behavior is around 95%. I managed to bring the pool down to 95%, now the writes get served continuously as it should be.
What is the explanation for this behaviour? Is it intentional and can the threshold be tuned? I experienced this on Sol10 U8. Thanks, Arne _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
