Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: raid level

Re: raid level

From: ORA600 <panandrao_at_gmail.com>
Date: 15 Dec 2005 22:36:16 -0800
Message-ID: <1134714975.961906.163580@g43g2000cwa.googlegroups.com>


Hi,

As much as i would like to agree with all on this post about RAID 0+1 or 1+0, there is one caveat you have to consider...

the no.of arms or disks available to your application(and Oracle) for servicing read/write requests is cut to half with RAID 0+1. These days, you can get 300 GB disks and a Terabyte worth of data can sit in about 6-8 disks! If you are running a r/w intensive application, no amount of IO balancing can help..because you don't have anything to balance! just 3-4 disks will be servicing all the needs of the application, don't even bother about the no.of users.

the key is IOps/seconds. What the peak and sustainable IO rate that the SAN box or disk system provide? what are the needs of your application? how does it access the data? predominantly reads or writes, etc.?

Whereas with RAID 5, you can have 70% of your disks servicing your read/write requests. I have seen many IO intensive application use RAID 5 successfully and with S.A.M.E technology. You have to get it right, then it works for you. There is, of course, a well documented slowness in write thoroughout when you compare it with RAID 0+1.

For your 2.2 TB SAN Box, you would surely have some cache. I would suspect 6-8GB may be available. So, that also needs to be considered.

Good luck!

cheers
anand Received on Fri Dec 16 2005 - 00:36:16 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US