On Fri, 2 Sep 2011 11:35:30 +0100 Michael Busby <michael.a.busby@xxxxxxxxx> wrote: > Great, will test that in a bit > > will mdadm 3.2.2 support converting raid4 to raid5 > > "A RAID4 can change the number of devices or the size of individual > devices. It cannot be converted to RAID5 yet (though that should be > trivial to implement)" I guess the man page needs updating. You would need a reasonably recent kernel... 2.6.30 or later. I guess that isn't so recent any more. NeilBrown > > On 2 September 2011 11:22, NeilBrown <neilb@xxxxxxx> wrote: > > On Fri, 2 Sep 2011 10:12:32 +0100 Michael Busby <michael.a.busby@xxxxxxxxx> > > wrote: > > > >> Thanks Neil > >> > >> Is there anyway back from raid0 to raid4 as i know once at raid0 i > >> will no longer be able to add any disks, in theory i could change > >> echo raid0 > /sys/block/md0/md/level,but this would require adding a > >> missing disk to the raid4 at the same time, not sure how easy that > >> would be todo > >> > > > > Yes, you can switch from RAID0 to RAID4 in much the same way as you switch > > from RAID4 to RAID0. > > You can then freeze/add-disk/change-size/unfreeze/wait/switch-back-to-RAID0 > > to add more devices. > > > > mdadm-3.2.2 should be able to do all this for you. i.e. you ask it to --grow > > a RAID and --add some disks at the same time, and it will do all the required > > magic. > > > > This hasn't been tested extensively, but should work in simple cases. > > > > Of course the more devices you have in a RAID0, the less reliability you have > > - but e.g. as a cache for a tape backup system a large RAID0 is fine. > > > > NeilBrown > > > > > > -- 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
