RE: RAID or NOT to RAID? What's the diff???

[Kevin Lange]

Title: RAID or NOT to RAID? What's the diff???

Take a look at http://www.acnc.com    Choose the raid.edu item on their menu bar (I think this brings you to http://www.acnc.com/04_00.html ) .    Read the explainations.

-----Original Message-----
From: Koivu, Lisa [mailto:[EMAIL PROTECTED]]
Sent: Monday, August 13, 2001 11:06 AM
To: Multiple recipients of list ORACLE-L
Subject: RAID or NOT to RAID? What's the diff???

Good morning -

Admitting ignorance here.  What is the difference between Raid 0+1 and Raid 1+0  (is this mirroring)?  If someone can forward a website that describes the difference I would really appreciate it.

Thanks
Lisa Koivu
Oracle Database Administrator
Fairfield Resorts, Inc.
954-935-4117

-----Original Message-----
From:   Jonathan Lewis [SMTP:[EMAIL PROTECTED]]
Sent:   Saturday, August [Koivu, Lisa]  11, 2001 4:25 AM
To:     Multiple recipients of list ORACLE-L
Subject:        Re: Fwd: RE: RAID or NOT to RAID?




You could also mention that when you have
to resilver on RAID 1+0 after a disk fails,
you only have to resilver one disk.

On RAID 0+1 you have to resilver all the
disc in the stripe.




Jonathan Lewis

Seminars on getting the best out of Oracle
Last few places available for Sept 10th/11th
See http://www.jlcomp.demon.co.uk/seminar.html






-----Original Message-----
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Date: 11 August 2001 01:13




|
|For e.g, if you have a 2-way striped mirrored volume,
|when you lose 1 drive in the volume, with RAID 0+1 you
|will lose 50% of the logical volume's I/O capacity, as
|the whole member of the logical volume is shot,
|because the stripe becomes totally invalid. With a
|comparable configuration using RAID 1+0, you will lose
|only 25% of your logical volume's I/O capacity.
|
|When the striped volume is a 4-way stripe, again with
|1 drive loss, with RAID 0+1 you will lose 50% of I/O
|capacity versus with RAID 1+0, you will only lose 12
|1/2 %. As your stripe-width increases, the percentage
|loss in the I/O capacity for RAID 1+0 decreases.
|
|You should (when possible) consider using RAID 1+0 any
|day when compared to RAID 0+1.





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