VA7100 Configuration

[Cara Tock]

I have a hp virtual array and I need to configure the luns for use with an oracle database. I need about 80 GB of space for each instance of the database. Is there any advantage, for example, to configure 10 luns at 8GB a piece as opposed to 1 lun at 80GB? Any opinion would be appreciated.

[Martin Johnson]

Using only one LUN will give you a bottleneck. Multiple LUNs will give you faster throughput. I'm not sure if you need 10 LUNs. You may be able to get away with 4.

HTH
Marty

[Vincent Fleming · Accepted solution]

The VA7100 is an AutoRAID box, so it's a bit different than traditional arrays.

I would suggest 2-3 LUNs for a database: one for logs, one for indices, and one for tablespaces.

Depending upon your database size vs. total capacity of the array, the VA may put your tablespaces in RAID 5, but would keep the logs (which have frequent sequential writes) in RAID 0/1. If you use less than 1/2 of the usable space of the array in AutoRAID mode, it will keep everything in RAID 0/1.

More LUNs than that will not increase your performance.

Good luck!

[MaSa_3]

I have got the same idea, split a large LUN in to some piece.

And then I want put them together with HP-UX LVM agin.
The idea is to have more fexibilty for expanding and
shrinking diskspace later wihtout a system outage by recrating a resized LUN.

I have to some BC scripting for backup an Usertest usages
OK it will be a bit more complicated -> no problem.

Any opinons to that idea.

[Roger_22]

First there are two good performance papers on hp.com;

http://www.hp.com/products1/storage/products/disk_arrays/midrange/da_perf_guide.pdf

http://www.hp.com/products1/storage/products/disk_arrays/infolibrary/va_perf_analysis.pdf

A couple of point to remember:

One LUN per RG (you failed to indicate your array model) is sufficient to get all the performance from the array ??? multiple LUNs do not increase the array performance. However, the system (the OS and application) must create enough concurrency thru the existing LUNs to demonstrate maximum array performance ??? this is particularly important for read operations (array write caching creates its own concurrency). The two components of this are OS driver queue depth per LUN and application concurrency.

If you have a 7400 or 7410, each RG is like an independent array. RGs can have a different number and type of disks installed, and (if the array is configured in the AutoRAID mode), one RG can be AutoRAID and the other RAID 1+0. This is managed by the LUN allocated capacity ??? if the space needed for the reserved LUNs can fit in RAID 1+0, then that???s what the array will use. If your interested, reply with the desired RAID 1+0 space, the type of disks you have, and I???ll tell you the magic capacity for RAID 1+0 only operation.