Re: stripe size

[AK]

Title: Message

One more thing to consider in stripe size is the type of application if its a oltp or dss . In stripe size is 8k on 3 disks which means oracle can read 24k in parallel which traslates to 3 blocks. If application really looks for 3 blocks at a time ??   on high read system a stripe size of 32k on 3 disks can make 12 block read at parallel .   I think Ahmed Alomari has some good stuff on io tuning in book 'Oracle and Unix performance tuning '.     -ak     ----- Original Message ----- From: Matthew Zito To: Multiple recipients of list ORACLE-L Sent: Tuesday, August 19, 2003 9:59 AM Subject: RE: stripe size   Depends on the storage being used and the number of spindles.  I definitely wouldn't go any smaller than 8k, but 8k is probably fine on a JBOD array, especially if you're matching your filesystem block size to your oracle block size to your stripe size.  You might want to look at changing it to 16k if you're using high-speed disks and let the disk firmware's read-ahead and large cache give you a bit of a boost.  You're probably not talking about a huge jump, though - only if you're really saturating your disks will you notice a difference.   As I've said in the past, the rules change completely when you're using a "smart" array like a Hitachi lightning or an EMC symmetrix, or even a smaller one like a Clariion or HP EVA.  For those, engage your vendor's performance engineers or hire someone like me to come in and tune your storage, or just invest a lot of time in learning how your array works and experiment.   You should look at using VxFS as well - you can eliminate double-buffering and get asynch kernel i/o, which alone could provide much better throughput.  Depending on your Solaris version, as well, you could be creating unnecessary memory pressure by using UFS.   Thanks, Matt -- Matthew Zito GridApp Systems Email: [EMAIL PROTECTED] Cell: 646-220-3551 Phone: 212-358-8211 x 359 http://www.gridapp.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Roger Xu Sent: Tuesday, August 19, 2003 12:35 PM To: Multiple recipients of list ORACLE-L Subject: RE: stripe size We are running Solaris with Veritas Volume Manager (not vxfs, but ufs) 8k block size. For better performance, how big the stripe size should be? 8k? -----Original Message----- From: Matthew Zito [mailto:[EMAIL PROTECTED] Sent: Monday, August 18, 2003 11:19 PM To: Multiple recipients of list ORACLE-L Subject: Re: stripe size   As long as you're using software RAID and not hardware, you can use vxprint to give you that information.  I believe a functional syntax that includes the stripe size is vxprint -hrt -g (diskgroup) .  If you're using hardware RAID, you're going to need whatever array management tools your vendor cheerfully provided you.   Hope this helps, Matt   ----- Original Message ----- From: AK To: Multiple recipients of list ORACLE-L Sent: Monday, August 18, 2003 11:29 PM Subject: stripe size Is there any command on hp-ux which can tell me on what disks particular file is striped on and stripe size .   Hp-ux ( 11 )     Thanks, ak For technical support please email [EMAIL PROTECTED] or you can call (972)721-8257. This email has been scanned for all viruses by the MessageLabs Email Security System.