Hi, My customer says: ------------------------------------ Application has NFS directories with millions of files in a directory, and this can''t changed. We are having issues with the EMC appliance and RPC timeouts on the NFS lookup. I am looking doing is moving one of the major NFS exports to as Sun 25k using VCS to cluster a ZFS RAIDZ that is then NFS exported. For performance I am looking at disabling ZIL, since these files have almost identical names. What are Sun''s thoughts on this? ------------------------------------ Thanks for any insight. -- Joe Cicardo Systems Engineer Sun Microsystems, Inc. joe.cicardo at sun.com 972-546-3887
On 11/18/09 12:21, Joe Cicardo wrote:> Hi, > > My customer says: > > ------------------------------------ > Application has NFS directories with millions of files in a directory, > and this can''t changed. > We are having issues with the EMC appliance and RPC timeouts on the NFS > lookup. I am looking doing > is moving one of the major NFS exports to as Sun 25k using VCS to > cluster a ZFS RAIDZ that is then NFS exported. > > For performance I am looking at disabling ZIL, since these files have > almost identical names.I think there''s some confusion about the function of the ZIL because having files with identical names is irrelevant to the ZIL. Perhaps the customer is thinking of the DNLC, which is a cache of name lookups. The ZIL does handle changes to these NFS files though, as the NFS protocol requires they be on stable storage after most NFS operations. We don''t recommend recommend disabling the ZIL as this can lead to integrity of user data issues. This is not the same as zpool corruption. One way to speed the ZIL up is to use a SSD as a separate log device. You can check how much activity is going through the ZIL by running zilstat: http://www.richardelling.com/Home/scripts-and-programs-1/zilstat Neil.
On Wed, 18 Nov 2009, Joe Cicardo wrote:> > For performance I am looking at disabling ZIL, since these files have almost > identical names.Out of curiosity, what correlation is there between ZIL and file names? The ZIL is used for synchronous writes (e.g. the NFS write case). After a file has been opened, it would be very surprised if ZFS cared about the file names since actual files are identified by an inode. Only directory lookups would see these file names. It is pretty normal that when a directory contains millions of files, that they use almost identical names. Are the NFS operations which are timing out directory lookups, ''stat'', or ''open'' calls? If files are also being created at a rapid pace, the reader may be blocked from accessing the directory while it is updated. Bob -- Bob Friesenhahn bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/