Max Waterman <davidmaxwaterman@xxxxxxxxxxxxxx> wrote: > For example, if you have raid1 array, and have an 'extra' spare (is > spare the correct word) on a removable drive, then it can be A spare is not enough, since spares get not synched. > Is this a crazy idea? Have people thought of this before? Are there > any other gotchas? I'm doing my backups this way quite a long time now. All my RAID1 have an empty slot (i.e. I'm running 3-mirror RAID1s degraded to 2 mirrors) where I plug my backup disks in from time to time. For the bigger RAIDs I'm using bitmaps to reduce the backup-time. However, I would never suggest my way to "the average user". There are lots of things you can easily do wrong. Especially if you do this on-line: You have to make sure the filesystem is in a clean state when you pull the backup-disk. With bitmaps, only one backup generation works. etc. pp. Not to mention all the gotchas "the average fool" would stumble upon... synching in the wrong direction and things like that :) Btw... The Intel Matrix Storage Manager has a "mirror on demand" feature that seems to do something similar. I don't know how they deal with inconsitent filesystem states, etc. regards Mario -- There are two major products that come from Berkeley: LSD and UNIX. We don't believe this to be a coincidence. -- Jeremy S. Anderson -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
