Re: RAID-10 near vs. RAID-1

[Reindl Harald <h.reindl@thelounge.net>]

Am 12.06.24 um 02:14 schrieb Paul E Luse:
> On Wed, 12 Jun 2024 01:04:18 +0200
> Reindl Harald <h.reindl@thelounge.net> wrote:
> 
>>
>>
>> Am 11.06.24 um 20:31 schrieb Piergiorgio Sartor:
>>> I'm setting up a system with 2 SSD M.2 (NVME).
>>>
>>> I was wondering if would it be better, performace
>>> wise, to have a RAID-10 near layout or a RAID-1.
>>>
>>> Looking around I found only one benchmark:
>>>
>>> https://strugglers.net/~andy/blog/2019/06/02/exploring-different-linux-raid-10-layouts-with-unbalanced-devices/
>>>
>>> Which uses mixed SSD, NVME and SATA.
>>>
>>> Does anybody have any suggestions, links, or
>>> ideas on the topic?
>>>
>>> BTW, practically speaking, what's the difference,
>>> between the two RAIDs?
>>
>> i wouldn't even consider a RAID10 with two disks, especially with SSD
>> and practically you end with a unsupported RAID1 because there are no
>> stripes with 2 disks
>>
>>
> I don't disagree but I would recommend you try each variation and
> measure the performance for yourself.  It's a great learning experience
> if you haven't done it before and there's nothing like trusting your
> own data over on your own system/config something that someone else has
> done when there are so many factors that can affect performance.

the problem with benchmarks is that they often don't reflect mixed, 
real-world performance - for virtual machine workload the "far" layout 
wins in case of HDD

with NVME RAID i pretend it don't matter enough to even waste your time