On Thu Aug 16, 2012, NeilBrown wrote: > On Thu, 16 Aug 2012 17:28:13 -0600 Thomas Fjellstrom <thomas@xxxxxxxxxxxxx> > > wrote: > > On Sun May 6, 2012, NeilBrown wrote: > > > On Mon, 7 May 2012 00:32:35 +0000 Garðar Arnarsson <gardar@xxxxxxxxxxx> > > > > wrote: > > > > That's an excellent idea, I was going to add another disk for extra > > > > space right after migrating to raid6. > > > > > > > > Just to be clear, I'll be running the normalize attribute just once > > > > to straighten the array out right? Or will I have to do it for every > > > > extra drive I add in the future? > > > > > > Just once. > > > > > > > And what are the N+1 you mention in --raid-devices=N+1 > > > > > > By "N+1" I just meant "1 more than the number of devices currently in > > > the array". > > > > > > If you have both new devices ready to go, you just do a single reshape > > > operation that converts to RAID6 and adds more space. This does not > > > need a backup file and is probably the best approach. > > > > > > If you currently have a 10-drive RAID5 and want a 12-drive RAID6, then > > > > > > mdadm --grow /dev/md0 --raid-devices=12 --level=6 > > > > > > is what you want. > > > > I apologize for bringing back a long dead thread, but I've been wondering > > if mdadm does the grow op in this case, in one step? Or does it > > internally do each step separately, doing a reshape with each one? > > > > I've currently got a 7x1TB disk raid5, and have a couple more disks to > > add and I was planning on moving to raid6. I'm hoping to reduce the > > amount of time the array is "reshaping" because I'm a bit paranoid that > > my bad luck with hard drives will decide to hit right then and there. > > If you change the level and the number of devices in the one command, and > there are already enough spares present to satisfy the requirements of the > new size, then it will only perform a single reshape operation which will > use the minimal amount of time. Ah. Thank you for clarifying that for me :) just running the two new drives through a bit of a stress test. Then I'll get to expanding the array. Thanks. > NeilBrown -- Thomas Fjellstrom thomas@xxxxxxxxxxxxx -- 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
