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Re: Which oracle server ?

From: DA Morgan <damorgan_at_x.washington.edu>
Date: Sun, 12 Dec 2004 21:02:17 -0800
Message-ID: <1102914028.50143@yasure>


Howard J. Rogers wrote:

>> You don't want to use raid 5.  

>
> He might do.
>
> HJR
Source:
http://download-west.oracle.com/docs/cd/B14117_01/server.101/b10752/instance_tune.htm#23421 Quote:
"Move the redo logs to faster disks or a faster I/O subsystem (for example, switch from RAID 5 to RAID 1)."

Source:
http://download-west.oracle.com/docs/cd/B14117_01/server.101/b10752/iodesign.htm#26022 Quote:
"Avoiding the use of RAID 5 for redo logs."

Source:
http://download-west.oracle.com/docs/html/B13831_01/tuning.htm#sthref531 Quote:
"Striping data across a number of disks is one example of a redundant array of inexpensive disks (RAID). There are several different types of RAID, also referred to as RAID levels, ranging from high performance to high reliability. The three most common RAID levels in Oracle Database installations are RAID-0, RAID-1, and RAID-5. Descriptions of each RAID level follow Table 7-2, which shows each level's read and write penalties.

RAID Level 		Read Penalty  	Write Penalty
0 (Disk Striping) 		1:1 	1:1
1 (Disk Mirroring) 		1:1 	2:1
0 + 1 				1:1 	2:1
5 (Distributed Data Gathering) 	1:1 	4:1"
.. and ..
"The write penalty of 4:1 results from 2 reads and 2 writes during parity calculation."

Source:
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96533/iodesign.htm#22610 Quote:
"RAID 0+1: Striping and Mirroring

This level combines the technologies of RAID 0 and RAID 1. It is widely used because it provides good reliability and better read and write performance than RAID 1."
and
"RAID 5 striping is similar to striping in RAID 0 ... while write performance can suffer. This configuration might not be ideal for write-intensive applications."

You are, of course, correct as always and I have obviously misunderstood. Thank you, in advance, for correcting both me and Oracle.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)
Received on Sun Dec 12 2004 - 23:02:17 CST

Original text of this message

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