How to recover data from dead hard drive.

Steve O'Hara-Smith steve at
Sat Oct 21 21:08:12 UTC 2017

On Fri, 20 Oct 2017 10:11:21 +0000
Carmel NY <carmel_ny at> wrote:

> Personally, my confidence in hardware RAID far exceeds that of software
> based RAID without regards to the OS. Of course, YMMV.

	In order of decreasing reliability:

	ZFS mirror - at least three ways

	ZFS raidz2 (perhaps equal in reliability to the mirror - but slower)
	Hardware mirror - at least three ways

	Hardware RAID6

	Software mirror - at least three ways

	Software RAID6

	Anything without at least two drive redundancy is not reliable IMHO,
when a drive fails you have no redundancy until a replacement is installed
and populated - which is bad enough if you have a hot spare but if you have
to wait for an order cycle or worse yet for an RMA that can be an
uncomfortably long time to be at risk.

	Hardware falls behind ZFS mainly because of the protection against
silent corruption in ZFS and raidz2 lacking the write hole of RAID6.

Steve O'Hara-Smith <steve at>

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