Re: Which RAID level?

Thanks,

So, then, 0+1 for performance and 1+0 for safety?

Carlos.

jason_at_seahorse.demon.co.uk (Jason Salter) wrote:
> Imagine you had 10 discs, you could stripe the first 5 and then mirror
> them (Raid 0+1). Or you could mirror 5 disks and then create a stripe
> across the mirrors (Raid 1+0).
>
> With Raid 0+1, you could lose up to two disks (one from each stripe
> set) before your system would go down (assuming you have no hot
> swaps).
>
> With Raid 1+0, you could lose up to six disks (one from each mirror
> pair) before your system would collapse.
>
> I think this is the difference ;)
>
> Regards,
> Jason.
>
> On Fri, 06 Aug 1999 22:24:56 GMT, cpereyra_at_ix.netcom.com wrote:
>
> >My understanding is that Raid 0+1 (striping and mirroring) is best
for
> >performance and the most expensive. Raid 5 is OK but suffers from
some
> >performance penalty during writes. I am sure that you are going to
get
> >a lot of advice on this subject, so for the next person, if you know
> >the answer could you explain the difference between 0+1 and 1+0? I
> >know that one is preferred over the other but not sure how or why.
> >
> >Thanks,
> >
> >Carlos.
> >In article <37AB0AD9.311E2E9C_at_us.oracle.com>,
> > Steven Poe <spoe_at_us.oracle.com> wrote:
> >> Breno,
> >>
> >> I don't believe it is so much the database itself, but how safe do
> >you want
> >> your data? RAID0 will allow you to stripe across all your drives
> >with no
> >> redundancy. If one drive fails, it is dead. RAID1 is a mirror of
> >your
> >> main drive(s). You can run, or should be able to, run RAID1 on
top of
> >> RAID0. RAID5 allows for rundundancy/CRC checks so if one drive
dies,
> >the
> >> other drives keep working. I speaking from my experience with
Linux,
> >I
> >> think NT would be the same, but I cannot assure you of that. If you
> >have
> >> nightly/backups, you *may not* need a mirror (RAID1) but that will
> >also
> >> depend on the availability of your database too. There can be
> >arguments
> >> for each case.
> >>
> >> -Steven Poe
> >>
> >> Breno de Avellar Gomes wrote:
> >>
> >> > I am about to install high availability Oracle8i FailSafe using
SMP
> >and
> >> > RAID Compaq Servers (Intel) running NT 4.0.
> >> > Some DBA advised me to use RAID level 0/1, others 5. It seems to
be
> >> > controversial.
> >> >
> >> > Wich level is more adequate? Why should I use one instead
another?
> >> >
> >> > Thanks in advance
> >> >
> >> > Breno
> >>
> >>
> >
> >
> >Sent via Deja.com http://www.deja.com/
> >Share what you know. Learn what you don't.
>
>

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't. Received on Mon Aug 09 1999 - 18:17:00 CDT