MetaLUN vs. single LUN n my setup instance CX500

Question

Hi.

I have 8 146GB 10k RPM FC drives that I would like to use only for a new Oracle test DB server running RH AS 4. Is there a reason why I wouldn't set it up as one large LUN vs. many metaLUN's?

thanks

dynamox · Answer

I would set it up as a few smaller luns in your volume group so PowerPath will have more queues to drive IO through.

dynamox · Answer

sure, i see that you already asked a question about white papers about oracle on Clarrion. I would actually have separate volume groups for my database and for my archive/recovery logs. I know it's a test server but as you move to production you might have a performance need to place logs on say RAID10 Luns while database resides on RAID5 Luns. Having them in different volume groups will be easier to manage from LVM perspective, plus if you later on decide to do something with SnapView/MirrorView it will be easier to deploy things.

Karl999 · Answer

Most of my experience on this SAN (which is also my first) is with VMware but I think I know what you are referring to.

I should present x number of smaller LUNs to Linux and create one volume group from those LUN's?

fullers1 · Answer

Before you ask the LUN question I think you need to evaluate the RAID Group question. How you carve the LUNs almost doesn't matter if you put all 8 disks in one RAID Group.

If, you want to keep log file transaction I/Os and database transactions I/Os from afftecting each other, you will need to put some of the disks in one RAID Group and some in another so you have two independent RAID Groups. Then carve the database LUN from one RAID Group and the log file LUN from the other.

Meta LUNs only help if each component LUN comes from a different RAID Group. I've learned this the hard way. You actually take a performance penalty if you create a Meta LUN from LUNs in the same RAID Group.

CLARiiON

MetaLUN vs. single LUN n my setup instance CX500

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