Обсуждение: 3 disks configured RAID 0 over 10 disks configured in RAID 5 (self replicating SAN)

Does your controller support odd number RAID-10 i.e. RAID 1E?  If so
then 3 disks in RAID-1E. Or better 10 disks in 1E

On Tue, Aug 27, 2013 at 4:33 PM, Rene Romero Benavides
<rene.romero.b@gmail.com> wrote:
> Thanks for your attention.
> What would you choose for a postgresql installation: 3 disks configured with
> RAID 0 (in a self replicating SAN) over 10 disks configured with RAID 5
> (also in a self replicating SAN) , we have space constraints that prohibit
> us from choosing RAID 1+0.
> I've been persuaded to choose RAID 5, because writes and parity computation
> will be spread over 10 disks compensating write overhead providing a better
> level of data security.
>
> Do you think it was a good decision? Any comment will be appreciated. Have a
> good day.
>
> --
> El genio es 1% inspiración y 99% transpiración.
> Thomas Alva Edison
> http://pglearn.blogspot.mx/
>



--
To understand recursion, one must first understand recursion.

On Tue, Aug 27, 2013 at 7:18 PM, Rene Romero Benavides
<rene.romero.b@gmail.com> wrote:
> First of all, thank you so much for your valuable time.
>
> It probably does, though we have a requirement of having available at least
> twice the expected database size, and 50% of disk space overhead sounds like
> too much for us to take in a replicated SAN environment and a PostgreSQL
> master/slave - streaming replication setup.
>
> our options regarding disks availability at the moment are:
>  a 3 disks array dedicated for PostgreSQL in any RAID configuration we'd
> like
> OR
> a 10 disks array shared with 14 virtual machines running the middleware
> layer and the application infrastructure in a RAID 5 configuration
>
> again, I do really appreciate your kindly help.

Whatever you do do NOT put postgresql on a RAID-5 array if you can
help it. Can you steal a few disks for a 4 or 5 disk RAID 1E?

In your case I'd go for the 3 disk raid 0 setup.
El ago 27, 2013 11:25 p.m., "Scott Marlowe" <scott.marlowe@gmail.com> escribió:
>
> On Tue, Aug 27, 2013 at 7:18 PM, Rene Romero Benavides
> <rene.romero.b@gmail.com> wrote:
> > First of all, thank you so much for your valuable time.
> >
> > It probably does, though we have a requirement of having available at least
> > twice the expected database size, and 50% of disk space overhead sounds like
> > too much for us to take in a replicated SAN environment and a PostgreSQL
> > master/slave - streaming replication setup.
> >
> > our options regarding disks availability at the moment are:
> >  a 3 disks array dedicated for PostgreSQL in any RAID configuration we'd
> > like
> > OR
> > a 10 disks array shared with 14 virtual machines running the middleware
> > layer and the application infrastructure in a RAID 5 configuration

In your case I'd go for the 3 disk raid 0 setup. Be sure to have your failover scripts tested.

Regards,
Fernando