RE: Re[2]: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS

RAID 1+0 does so have parity. The formula is

        parity_bit = data_bit

:)

In this sense, RAID 1+0 is simply a special case of RAID 5. RAID 1+0 /is/ RAID 5 with G=2.  

Cary Millsap
Hotsos Enterprises, Ltd.
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-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jared.Still_at_radisys.com
Sent: Thursday, September 09, 2004 4:37 PM To: edgar.chupit_at_rs.lv
Cc: Oracle-L_at_freelists.org; oracle-l-bounce_at_freelists.org Subject: Re: Re[2]: Raid5 Vs Raid0+1 -- Raw Vs Solaris 9 Concurrent Direct IO UFS
> Unless I'm missing something than according to raid specs it doesn't
> mater how many disks are in raid5 array, you just need one additional
> disk for checksums, so in case of 6 spindle array you can create raid5
> that will operate according to your schema (it actually will be two
> raid5 arrays) or you can create one raid5 array that will use 5 disks
> for data and one disk for checksums.
>
> Please, correct me if I'm wrong.
>

It sounds to me like you are describing a RAID volume with dedicated parity. If so, that is RAID 3.

RAID 5 has distributed parity.

RAID 1+0 has no parity. ;)

Jared

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