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Load Balancing / Utilise other LUN / Oracle

Occasional Contributor

Load Balancing / Utilise other LUN / Oracle

Hello all,
I currently have Oracle 8.1.7 running on a hp9000 with RAID 5 configuration. I'm not a UNIX guru, it's all new to me. I want to have datafiles on separate disks, but I don't know how to achieve this with this configuration. All the datafiles could be on the same disk for all I know!
The Oracle datafiles are setup in vg01 - 3 physical volumes (6 18Gb disk, raid 5), 4 logical volumes, VxFS. It appears that all my logical volumes are only spanning the same LUN (6 disks). Is there a way for me to segregate the LV's to span LUNs or is there a way for me to put the datafiles on separate disks (or LUNS), or move LV's to another LUN, or create a LV on a specific LUN, or at least ensure that datafiles are being stored on separate disks? Your help woould be greatly appreciated. I believe our data warehouse is running like a DOG because of this.


Timothy Ingersoll_1
Occasional Visitor

Re: Load Balancing / Utilise other LUN / Oracle

First I suggest that you change to RAID 1 with HP Mirror/UX. This gives you the ability to specify the drive/lun drive arrangement for your mirrored drives.

I also recommend that you consider consider smaller extend sizes when you use the lvcreate/lvextend command. This also can give a great improvement in performance.

IF you are using multiple connections to the drive, I suggest that drives be reconfigured to take advantage of the issue of multiple con-currently.
Sridhar Bhaskarla
Honored Contributor

Re: Load Balancing / Utilise other LUN / Oracle

HI Con,

It is difficult to balance/distribute the load on the already configured disk. The best you can do is to find out hot files and move them onto other disks. It means moving to other filesystems and volume groups. You have to do some permuations and combinations here.

Depending on the RAID you have, it may be possible for you to go for LVM/extent level striping.

LVM striping can help in distributing the files but also in load balancing the paths to the maximum. You will have to careful with the stripe size though based on how your RAID is setup.

Extent Level striping may not be better than LVM but still is better than not having striping at all.

But the performance is dependent on the nature of I/O that your system produces.

There are some drawbacks with the striping like future expansion, etc., Look at for further information. Man page of LVM and lvcreate will also help you to get more details.

You may be disappointed if you fail, but you are doomed if you don't try