Hello Matthew, Monday, October 16, 2006, 5:07:50 PM, you wrote:
MA> Robert Milkowski wrote: >> Hello zfs-discuss, >> >> S10U2+patches. ZFS pool of about 2TB in size. Each day snapshot is >> created and 7 copies are kept. There's quota set for a file system >> however there's always at least 50GB of free space in a file system >> (and much more in a pool). ZFS file system is exported over NFS. >> >> Snapshots consume about 280GB of space. >> >> We have noticed so performance problems on nfs clients to this file >> system even during times with smaller load. Rising quota didn't >> help. However removing oldest snapshot automatically solved >> performance problems. >> >> I do not have more details - sorry. >> >> Is it expected for snapshots to have very noticeable performance >> impact on file system being snapshoted? MA> No, this behavior is unexpected. The only way that snapshots should MA> have a performance impact on access to the filesystem is if you are MA> running low on space in the pool or quota (which it sounds like you are MA> not). MA> Can you describe what the performance problems were? What was the MA> workload like? What problem did you identify? How did it improve when MA> you 'zfs destroy'-ed the oldest snapshot? Are you sure that the oldest MA> snapshot wasn't pushing you close to your quota? I wasn't on-site every-time it happened... but it looks like all NFS clients to that file system have problem accessing data for 2-5s and iostat on clients shows 100% busy to the disk. There was well over 100gb of free space in a file system, then rising quote to add another 100gb didn't help. After removing snapshots all problems disappeared almost immediately. No new snapshots were created during this time. It happened second time - and again, quite a lot of free space and destroying one snapshot helps. If it happens again I'll try to get some more specific data - however it depends on when it happens as during peak hours I'll probably just destroy a snapshot to get it working. -- Best regards, Robert mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
