2009/12/8 Robin Hill <robin@xxxxxxxxxxxxxxx>: > On Tue Dec 08, 2009 at 09:01:23PM +0800, hank peng wrote: > >> Hi, all: >> As we know, when a raid5 array is created, recovery will be going on >> which involves some read, one xor and one write. Since there is no >> real data in the disk at the time, besides, if I am willing to wait >> for recovery to complete and then use this raid5, how about adding >> support for a fast recovery method? Right now, what is in my mind is >> zero all disks which belong to this raid5. I think it will increase >> raid5 recovery speed when created and decrease CPU usage, since all >> zero is also XORed. >> What do raid developers think? >> > It'll decrease CPU usage but increase I/O - you're now needing to write > to all disks. Most systems will be I/O limited rather than CPU limited, My CPU is an embedded arch, 1.3GHz, single core, so CPU usage is important. In low-end NAS box, I think, this requirment is normal. > so the current approach works better. If you want to zero the disks > then do this before creating the array - you can then use --assume-clean > to skip the resync process. > > Cheers, > Robin > -- > ___ > ( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> | > / / ) | Little Jim says .... | > // !! | "He fallen in de water !!" | > -- The simplest is not all best but the best is surely the simplest! -- 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
