VA-7100 lun configuration

[Giorgio Milanesio_1]

Hi to all,
I've a question about lun configuration on va7100. Is possible to configure one disk for each lun? For example: I've 4 disks for data and 4 disks for mirrors or raid, and I want to configure 4 luns; I want the first lun on first disk, the second lun on second disk, ecc.
Any idea?

Thanks

[Eugeny Brychkov]

No, this is virtual array and when you create LUNs VA allocates data in the way it has best perfomance and redundancy. Disks are not dedicated for LUNs, all LUNs are spread across all the disks for the same reasons
Eugeny

[Giorgio Milanesio_1]

But if I've an oracle DB and I want separate data from index and I want be sure that the I/O operations on data don't slow down the I/O operation on index?

Thanks

[Peter Mattei]

This is not what ORACLE is recommending.
They promote what we already did for years: Stripe as much as possible.
Read the following http://otn.oracle.com/deploy/performance/pdf/opt_storage_conf.pdf and
http://otn.oracle.com/tech/hp/storage.pdf

The VA7100 perfectly fits into SAME and adds ease of management! So go ahead with your VA7100.

Cheers
Peter

[scott fuhrman_2]

This would also defy the purpose of purchasing and array. Not only would you lose the speed of multiple disks, you would also lose the redundancy and it would make it much easier to lose data.

Your best bet would be to set the array up normally, and not keep the VA very full so it stays in RAID0+1 mode, and it would be faster than if the array was using RAID5.

If you wanted to do what your originally stated, it sounds like you should have just bought a JBOD. But the VA will suit your (and Oracles) needs much better. Trust me.

[Tim D Fulford]

Hi

I'd just like to add some other things to the above. Oracle does premote SAME disk poicy.

The advantage with a VA7100 is that you can create your LUNs at ANY size (obviously there is an upper limit). Thus you can provide a single SMALL(ish) LUN for your redo logs etc. By giving your database more LUNs you allow the work to be spread more evenly across them. I generally would reccomend RAID1+0 and only configure to about 1/2 the number of disks. So in your case you have 8 disks, 4 LUNs, BUT you could make a couple of the LUNs slightly larger. This way you do not "waste" space.

Alternatively, go for easiest, no brainer approach (we do!) Configure as 4 LUNs in straight RAID1+0 and put into one volume group & cut into appropriate LVs. You do not really need to stripe across these LUNs as the VA already does this for you, but you could use kilobyte or extent stripes if you want (BTW the VA stripes at 256kB across the disks if you want to avoid creating hot disks)

regards

Tim