On Wed, 20 Nov 2013, Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: > Hot spares are worse than useless. Especially for raid10. The drive takes > up space doing nothing but suck power, rather than adding space or > performance. Somehow this idea comes from cheap companies who seem to > think their data is so valuable they need hot spares, yet they don't have > 24/7 staff on hand to do a hot swap. (As if the only problem that can > occur is a dead drive.) So I think those companies can develop this > otherwise unneeded feature. > > n-copies raid1 is a good idea and I think it's being worked on. N copies RAID-1 is definitely more useful than RAID-1 with a hot-spare. But for RAID-5/RAID-6 a hot spare can provide real value. Not having to pay someone to make a special rushed visit to replace a disk is a definite benefit. Also when a disk isn't being used it doesn't draw much power. Last time I tested such things I found an IDE disk to use about 7W while spinning and no measurable difference to overall system power use when spun-down. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
