Am 01.12.2017 um 18:18 schrieb Wols Lists:
On 01/12/17 16:27, Reindl Harald wrote:
Am 01.12.2017 um 17:19 schrieb Nix:
That's not actually answering the question that was asked, y'know. If
you're against RAID 5 because the parity writes wear the drives out, you
should be much more strongly against RAID 10 for the same reason
RAID10 is simple mirroring of stripes
And?
why should mirroring on a different disk wear more?
The more I think about it, the more I come to the conclusion that
raid-10 is a bad idea for (a) minimising writes (and wear), and (b) for
safeguarding your data.
why?
Yes it does have advantages, and yes I plan to put a raid-10 array on my
new system, but if reducing wear or protecting data are your priorities,
raid-10 is the wrong choice
wrong!
rebuilds are much faster then with RAID5 or even RAID6 which is worst
and so the degraded timeslot is smaller, a RAID10 *can* survive two
faile disks while a RAID5 is for sure dead
RAID10 is practically a RAID1 with the performance enhancement of RAID0
and if the linux kernel would support "writemostly" on RAID10 as it does
with RAID1 it would be the perfect choice for a hybrid RAID for
workloads which are mostly read-bound and so combine all worlds (RAID0
at read from only the two SSD stripes, redundancy like RAID1 and only
the need of 2 SSD's and two HDD's for redundancy)
RAID5 has *zero* benefits against RAID10 except costs while RAID6 is
terrible for performance and wear out of disks
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