Hi all Sorry if my question is not very clear, I''m not very familiar with ZFS (why I ask this question). Suppose I''ve lot of low-cost raid array disk (like Brownie meaning IDE/SATA disk)) all in SCSI attachement (lot of ~ 10 and the sum of space is ~ 20 To). Now if I buy some ?high? level big raid array disk on FC attachement and a big Sun server, can I create a ZFS fs on all disks with : All data is on the new big raid array disk (using hardware raid) and All data is mirroring on the sum of my old low-cost raid array ? If it''s possible what do you think of the perf ? The purpose is make a big NFS server with primary data on a high-level raid array disk but using ZFS to mirror all data on the all old-raid-array. Regards. -- Albert SHIH Universite de Paris 7 (Denis DIDEROT) U.F.R. de Mathematiques. 7 i?me ?tage, plateau D, bureau 10 Heure local/Local time: Mon Dec 4 23:04:04 CET 2006
It is possible to configure ZFS in the way you describe, but your performance will be limited by the older array. All mirror writes have to be stored on both arrays before they are considered complete, so writes will be as slow as the slowest disk or array involved. ZFS does not currently consider performance in selecting a mirror side for reads, so half of the reads will run at the speed of the new array, half at the speed of the old array. If you need to use both types of arrays (20 To is a lot of space to give up!), consider creating two pools, one composed of newer arrays and one of older arrays, at least if your data is easily split into "fast" and "slow" sets (e.g. fresh data vs. archival, or database logs vs. infrequently-accessed tables). This message posted from opensolaris.org
Le 04/12/2006 ? 21:24:26-0800, Anton B. Rang a ?crit> It is possible to configure ZFS in the way you describe, but your performance will be limited by the older array. > > All mirror writes have to be stored on both arrays before they are considered complete, so writes will be as slow as the slowest disk or array involved. >OK. It''s possible to configure the server, the high level raid array, and the pool of my old array raid to do : 1/ When the server read/write he do from high level raid 2/ The server make a copie of all data from high level raid to the pool of my old array ?when he have the time?. But I want this automatics. I don''t want this by using something like rsync. What I want to do is make a NFS server with the new high level raid array with primary data. But I want also using my old-low-level raid array to make backup (in case I''m lost my high-level raid array) and only backup. Do you think ZFS can help me ? Best regards -- Albert SHIH Universite de Paris 7 (Denis DIDEROT) U.F.R. de Mathematiques. 7 i?me ?tage, plateau D, bureau 10 Tel : 01 44 27 86 88 FAX : 01 44 27 69 35 GSM(UFR) : 06 85 05 58 43 Heure local/Local time: Tue Dec 5 14:16:01 CET 2006
Hi Albert, On Tue, 2006-12-05 at 14:16 +0100, Albert Shih wrote:> It''s possible to configure the server, the high level raid array, and the > pool of my old array raid to do : > > 1/ When the server read/write he do from high level raid > 2/ The server make a copie of all data from high level raid to the > pool of my old array ??when he have the time??. But I want this > automatics. I don''t want this by using something like rsync.Using zfs send/recv, you can have one system running ZFS send copies to other systems running ZFS. It''s analogous to using rsync, but should be a bit quicker. I don''t know of an existing automated way to do this send/recv only when the sending zpool isn''t busy, for some given definition of "busy".. (you''re the 2nd person I''ve heard from in recent days that''s asked for this - Theo asked a similar question at http://blogs.sun.com/timf/entry/zfs_automatic_snapshot_service_logging#comments I wonder is it a useful RFE for the ZFS automatic snapshot service ? ) Here''s what I''m thinking: if you know what times the system is likely to be idle, you can use a cron job to send/receive the data between systems -- would this be sufficient ? Remember that you can send/recv incremental snapshots as well, so every 10 minutes, you could take a snapshot of your data, and decide whether to send/recv that (which would reduce the amount of IO you need to do) If the system is "busy", you just remember which incremental snapshot you last sent, and record that somewhere. As soon as the system is idle, take another snapshot, and do an incremental send of the difference between that and your recorded snapshot. This probably isn''t elegant, but it would do the job I think.> What I want to do is make a NFS server with the new high level raid array > with primary data. But I want also using my old-low-level raid array to > make backup (in case I''m lost my high-level raid array) and only backup.Sounds like you really want i/o throttling of send/recv operations as against "normal" pool operations - I don''t know enough to suggest how this could be implemented (except via brutal pstop/prun hacks on the "zfs send" process whenever your pool exceeds some given IO threshold) cheers, tim -- Tim Foster, Sun Microsystems Inc, Solaris Engineering Ops http://blogs.sun.com/timf
How about attaching the slow storage and kick off a scrub during the nights ? Then detach in the morning ? Downside: you are running an unreplicated pool during the day. Storage side errors won''t be recoverable. -r Albert Shih writes: > Le 04/12/2006 ? 21:24:26-0800, Anton B. Rang a ?crit > > It is possible to configure ZFS in the way you describe, but your performance will be limited by the older array. > > > > All mirror writes have to be stored on both arrays before they are considered complete, so writes will be as slow as the slowest disk or array involved. > > > > OK. > > It''s possible to configure the server, the high level raid array, and the > pool of my old array raid to do : > > 1/ When the server read/write he do from high level raid > 2/ The server make a copie of all data from high level raid to the > pool of my old array ?when he have the time?. But I want this > automatics. I don''t want this by using something like rsync. > > What I want to do is make a NFS server with the new high level raid array > with primary data. But I want also using my old-low-level raid array to > make backup (in case I''m lost my high-level raid array) and only backup. > > Do you think ZFS can help me ? > > Best regards > > -- > Albert SHIH > Universite de Paris 7 (Denis DIDEROT) > U.F.R. de Mathematiques. > 7 i?me ?tage, plateau D, bureau 10 > Tel : 01 44 27 86 88 > FAX : 01 44 27 69 35 > GSM(UFR) : 06 85 05 58 43 > Heure local/Local time: > Tue Dec 5 14:16:01 CET 2006 > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss