On Sat, Jun 01, 2019 at 11:31:51PM +0000, Andy Smith wrote:
> Okay. Which layout combinations are you interested in seeing results
> for? Obviously I've done 'n2' already as it's the default, so is it
> just 'f2' and 'o2' that you would be interested in? I don't think
> there is any point in changing the number of copies from 2, do you?
I see number of copies is limited to the number of devices anyway so
for me, 2 is the only option.
I tried out f2 and o2 (in addition to the n2 default that was
already done):
http://strugglers.net/~andy/blog/2019/06/02/exploring-different-linux-raid-10-layouts-with-unbalanced-devices/
TL;DR: For this setup non-default layouts were worse (~77% of
default) for sequential read and no different to default layout for
everything else.
I reran the benchmark several times for sequential read and got very
consistent results, so far/offset are definitely worse than near for
sequential 4KiB reads on these devices.
Cheers,
Andy
