On Wed, Dec 14, 2016 at 11:56 AM, Carlos E. R.
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On 2016-12-14 08:54, Andrei Borzenkov wrote:
On Wed, Dec 14, 2016 at 10:08 AM, Per Jessen <> wrote:
If it has it, it ought to be invoked automatically I would say. It's first and foremost priority should be to reduce the time in degraded mode.
How do you expect it to be invoked for a disk that is not present anymore? You can only rebuild using redundant information on remaining drives. Such migration must happen while disk is still present.
There might be a feature to start migrating to a new disk while the old disk is still connected and in use. At some point, when migration is completed, it switches over and tells the admin so that he can remove the old disk.
Of course, but it cannot be invoked when disk is pulled out already, which is the context of this sub-discussion.
There might be another feature to sync a hot spare disk periodically so that when it has to enter service the distance is not so great, only recent changes.
It is impossible unless you use RAID1 and with RAID1 it degrades to "triple mirror" that requires you to dedicate "spare" disk for each mirror, which is usually unacceptable as you lose too much space. You cannot "sync spare" because you do not know which disk is going to fail as so do not know what content spare will have. Even with single RAID group, not to mention global hot spare for multiple different RAIDs.
Another feature still would be to create a snapshot of the current status on another (bigger) disk, which can then be removed for archival or backup.
Archival/backup is orthogonal to data availability offered by RAID. But yes, you can replicate data to another device (or RAID) and sometimes transparently switch to another device (which presumes synchronous replication, otherwise any automatic switch over is disastrous). Any such solution obviously doubles amount of needed space. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org