On Wed, Jul 30, 2008 at 08:29:07PM +0200, Keld Jørn Simonsen wrote: > On Wed, Jul 30, 2008 at 12:18:06PM -0400, Bill Davidsen wrote: > > Richard Michael wrote: > > >Hello list, > > > > > >I'm building a new system with 8 disks, in two RAID5 arrays of 4 disks > > >each, and a RAID1 array across them. (Then LVM2 on top of the RAID1 > > >array.) > > > > > >I approached it this way for two reasons: > > > > > >1/ It feels "cleanest"; in the sense that it's not a special case, it's > > >just RAID1 with two devices, which happen to be RAID5. > > To me it seems muddy. Just having one big raid5 or raid10 would be cleaner and > give better performance. I can't have one big RAID5 because I want to split it in half regularly. I refer to it as "cleaner", because it treats the devices separately, which is what they are; one is RAID1 device, the other is a RAID5 device. Each is agnostic, and independent, with regard to the other. "Muddy" in my opinion is a mdadm hybrid RAID10, of which I need special knowledge. YMMV. > > >2/ I have a particular usage in mind: I need to be able to split > > >the mirror and remove half; return it later and resync. Therefore, > > >I want to know which disks comprise which halves. > > > I am not sure what you mean with this. You want to remove half of the > disks? I think you can do that with raid10, you just remove every > other disk. I have not tried that out, however. You could try it out > before actually emplouing it. Re-reading what I wrote, it's a mess of typos. :) But, yes, I want to remove half the disks on a regular basis, as off-site storage, and return them to the array for periodic resync. Regards, Richard -- 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
