Re: [gentoo-amd64] Is my RAID performance bad possibly due to starting sector value?

[Mark Knecht]

On Thu, Jun 20, 2013 at 12:27 PM, Rich Freeman <rich0@g.o> wrote:
> On Thu, Jun 20, 2013 at 3:10 PM, Mark Knecht <markknecht@×××××.com> wrote:
>>    Looking for some thoughtful ideas from those more experienced in this area.
>
> Please do share your findings.  I suspect my own RAID+LVM+EXT3/4
> system is not optimized - especially with LVM I have no idea how
> blocks in ext3/4 end up mapping to stripes and physical blocks.  Oh,
> and this is on 4k disks.
>
> Honestly, this is one of the reasons I REALLY want to move to btrfs
> when it fully supports raid5.  Right now the various layers don't talk
> to each other and that means a lot of micro-management if you don't
> want a lot of read-write-read cycles (to say nothing of what you can
> buy with a filesystem that can aim to overwrite entire stripes at a
> time).
>
> Rich
>

I'll share everything I find, true or false, and maybe as a group we
can figure out what's right.

In the meantime, please be careful with your RAID5 and do good backups
:-) I ran RAID5 for awhile but moved to RAID6 due to the number of
reports I read where one drive went bad on a RAID5 and then the RAID
lost a second drive before the original bad drive was replaced and
everything was gone.

Cheers,
Mark