It will wonderful to see that working, we badly need that capability of being able to remove a disk from a pool.
________________________________ From: James Dickens [mailto:jamesd...@gmail.com] Sent: 20 October 2009 03:39 To: Erik Trimble Cc: Unnikrishnan, Prasad (GE, Corporate); zfs-discuss@opensolaris.org Subject: Re: [zfs-discuss] Stupid to have 2 disk raidz? On Fri, Oct 16, 2009 at 1:40 PM, Erik Trimble <erik.trim...@sun.com> wrote: Prasad Unnikrishnan wrote: Add the new disk - start writing new blocks to that disk, instead of waiting to re-layout all the stipes. And when the disk is not active, do slow/safe copy on write to balance all the blocks? Conceptually, yes, doing a zpool expansion while the pool is live isn't hard to map out, conceptually. As always, the devil is in the details. In this case, the primary problem I'm having is maintaining two different block mapping schemes (one for the old disk layout, and one for the new disk layout) and still being able to interrupt the expansion process. My primary problem is that I have to keep both schemes in memory during the migration, and if something should happen (i.e. reboot, panic, etc) then I lose the current state of the zpool, and everything goes to hell in a handbasket. In a way I think the key of this working is the code for device removal, because when you are removing a device, you take from one and put on another, it should be much easier to use this code and move 1/N of existing data to a new device using functions from device removal modifications, i could be wrong but it may not be as far as people fear. Device removal was mentioned in the Next word for ZFS video. James Dickens http://uadmin.blogspot.com jamesd...@gmail.com -- Erik Trimble Java System Support Mailstop: usca22-123 Phone: x17195 Santa Clara, CA Timezone: US/Pacific (GMT-0800) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
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