md RAID10 questions

md RAID10 questions

[Miles Fidelman]

Hi Folks,

As far as I can tell, md RAID10 is the greatest thing since sliced bread 
- mirroring and striping in one operation (more efficient disk use, 
better performance), avoids the RAID5/6 write hole issue, etc. - I've 
been having very good luck with it on two servers that I run.

The thing is, I'm looking at some scaling and clustering options, and 
can find practically no documentation or case studies or much of any 
information about md RAID10 - which sort of surprises me.  I'd think it 
would be more popular and there'd be more comparisons vis-a-vis other 
options.

Anyway... what I'm looking at is trying to create a large storage pool, 
out of 16 drives, spread across 4 servers - essentially trying to create 
a poor man's storage cloud to support a collection of VMs that can be 
migrated for load leveling and failover.

One thought is to expose all the drives via AoE, then combine them into 
one large RAID10 array - but I'm neither sure this is feasible nor how 
it would perform under various loads, failure conditions, etc.

Thoughts, pointers, ....?

Thanks,

Miles Fidelman

-- 
In theory, there is no difference between theory and practice.
In<fnord>  practice, there is.   .... Yogi Berra

Re: md RAID10 questions

[keld]

On Mon, Oct 10, 2011 at 05:37:03PM -0400, Miles Fidelman wrote:
> Hi Folks,
> 
> As far as I can tell, md RAID10 is the greatest thing since sliced bread 
> - mirroring and striping in one operation (more efficient disk use, 
> better performance), avoids the RAID5/6 write hole issue, etc. - I've 
> been having very good luck with it on two servers that I run.
> 
> The thing is, I'm looking at some scaling and clustering options, and 
> can find practically no documentation or case studies or much of any 
> information about md RAID10 - which sort of surprises me.  I'd think it 
> would be more popular and there'd be more comparisons vis-a-vis other 
> options.
> 
> Anyway... what I'm looking at is trying to create a large storage pool, 
> out of 16 drives, spread across 4 servers - essentially trying to create 
> a poor man's storage cloud to support a collection of VMs that can be 
> migrated for load leveling and failover.
> 
> One thought is to expose all the drives via AoE, then combine them into 
> one large RAID10 array - but I'm neither sure this is feasible nor how 
> it would perform under various loads, failure conditions, etc.
> 
> Thoughts, pointers, ....?

there was some bencmarks on our wiki, but it is gone because kernel.org is down.

Any ideas how to remedy the wiki problem?

Best regards
keld

Re: md RAID10 questions

[Miles Fidelman]

keld@keldix.com wrote:
> there was some bencmarks on our wiki, but it is gone because kernel.org is down.
>
> Any ideas how to remedy the wiki problem?
>
Been wondering about that.  It's been a while now.  Sigh...


-- 
In theory, there is no difference between theory and practice.
In<fnord>  practice, there is.   .... Yogi Berra