Operating System - HP-UX
1748151 Members
3880 Online
108758 Solutions
New Discussion юеВ

Stripe Size / Stripe Width

 
oradba
Occasional Contributor

Stripe Size / Stripe Width

Can somebody clarify the following terminology for me, with respect to RAID configurations :

a. stripe size
b. stripe width
c. stripe interleave

5 REPLIES 5
Ron Cornwell
Trusted Contributor

Re: Stripe Size / Stripe Width

Here is a good article on striping for your review http://www.pcguide.com/ref/hdd/perf/raid/concepts/perfStripe-c.html
Sridhar Bhaskarla
Honored Contributor

Re: Stripe Size / Stripe Width

Hi.

a. stripe size

This is size of each chunk taken out from a disk normally specified in KB.

b. stripe width

The number of disks that constitute a striping group.

c. When a volume is striped, it does interleaving. So, I would say this as stripe size.

To illustrate the above, take four disks of 2 GB each. I can make a stripe volume of 8GB in such a way that the first 64 KB is accessed through Disk1, the next 64KB through Disk2 .. the fourth through Disk4 and the fifth 64KB through Disk1 again. It goes in this round robin fasion.

In the above case (considering I start it new), if I write 256KB of data sequentially, then it will be spread across 4 Disks which is interleaving.

In the above example, 64KB is the stripe size and 4 (disks) is the stripe width.

-Sri
You may be disappointed if you fail, but you are doomed if you don't try
Yogeeraj_1
Honored Contributor

Re: Stripe Size / Stripe Width

hi,

the above replies are excellent.

You may also wish to have a look at the attached document which discusses about Optimal Storage configuration for Oracle.

hth
Yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
Steven E. Protter
Exalted Contributor

Re: Stripe Size / Stripe Width

Great answers to your post.

You sound to me like an oracle dba, mostly based on your chosen handle here.

Oracle and I would like to advise against striping where the oracle data sits.

The best performance configuration would be RAID 10 or Raid 1/0

You'll want a 1 to 1 mirror of the disks that data sits on.

Example

/dev/vg01/oradata is in disk /dev/dsk/c1t2d0

lvextend -m 1 /dev/vg01/oradata /dev/dsk/c2t2d0

This mirrors the logical volume in the way I suggest. Obviously with oracle down. and the fs unmounted, unless you have onlineJFS.

Just a little free advice, striping is nice, but oracle data is better off in a Raid 1/0 situation.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Paddy_1
Valued Contributor

Re: Stripe Size / Stripe Width

Here is a little more documentation pertaining to oracle striping.Hope this helps
The sufficiency of my merit is to know that my merit is NOT sufficient