On Mar 22, 2010, at 7:30 AM, Svein Skogen wrote: > On 22.03.2010 13:54, Edward Ned Harvey wrote: >>> IIRC it's "zpool scrub", and last time I checked, the zpool command >>> exited (with status 0) as soon as it had started the scrub. Your >>> command >>> would start _ALL_ scrubs in paralell as a result. >> >> You're right. I did that wrong. Sorry 'bout that. >> >> So either way, if there's a zfs property for scrub, that still doesn't >> prevent multiple scrubs from running simultaneously. So ... Presently >> there's no way to avoid the simultaneous scrubs either way, right? You have >> to home-cook scripts to detect which scrubs are running on which >> filesystems, and serialize the scrubs. With, or without the property. >> >> Don't get me wrong - I'm not discouraging the creation of the property. But >> if you want to avoid simul-scrub, you'd first have to create a mechanism for >> that, and then you could create the autoscrub. >> > > Which is exactly why I wanted it "cooked in" in the zfs code itself. zfs > "knows" how many fs'es it's scrubbing.
Nit: ZFS does not scrub file systems. ZFS scrubs pools. In most deployments I've done or seen there are very few pools, with many file systems. For appliances like NexentaStor or Oracle's Sun OpenStorage platforms, the default smallest unit of deployment is one disk. In other words, there is no case where multiple scrubs compete for the resources of a single disk because a single disk only participates in one pool. In general, resource management works when you are resource constrained. Hence, it is quite acceptable to implement concurrent scrubs. Bottom line: systems engineering is still required for optimal system operation. -- richard ZFS storage and performance consulting at http://www.RichardElling.com ZFS training on deduplication, NexentaStor, and NAS performance Las Vegas, April 29-30, 2010 http://nexenta-vegas.eventbrite.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
