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how to use va7400 disks?

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faust2004
Regular Advisor

how to use va7400 disks?

Hi,exports,

We have two n4000 and Va7400, two controller, one switch.oracle ops will be installed, and the application is oltp, I am not sure of how to use
the va7400 disks.
I was told : when configure the va7400 disks, only 0+1 can be used. we have 28 *36G,
will so large 0+1 disk produce disk i/o performance problem? , does that mean that
all my data will be treated equally, no matter used frequencely or seldom used,
It seemed that I can do no thing about data distribute in raw disk level, but We can do so
in alpha box.
Can anybody give me a advice?

Thanks a lot
Sunny

3 REPLIES
harry d brown jr
Honored Contributor
Solution

Re: how to use va7400 disks?

Sunny,

The VA7400 is an AUTORAID box, which means that you have no control as to where data goes, and trust me, you don't want to. Let the AUTORAID take care of it, no need to micro manage your disks.

type in cmdviewVA if it doesn't return anything, then search for it:

find / -type f -name cmdviewVA

if that doesn't return anything, you need to install the SDM software!

Also, you should have an X display to use the GUI.

You create a LUN of whatever size you want, ioscan, and have at it.

live free or die
harry
Live Free or Die
Tom Moore
Occasional Advisor

Re: how to use va7400 disks?

Sunny,

The VA 7400 can run in "AutoRAID" mode or "1+0" mode. It provides for "Box Level" RAID control. This functionality is required to be set at initial configuration and cannot be changed w/o reformatting the array. However the VA family was designed to give high performance in RAID 5 DP (Double Parity). It does real well w/ Oracle applications in it's native AutoRAID mode.

Cheers,
Tom
Vincent Fleming
Honored Contributor

Re: how to use va7400 disks?

Hi Sunny;

Don't worry about disk bottlenecks with large 0+1 arrays - the reason they the VA uses large 0+1 arrays is that it gives better performance! The array also does AutoRAID, which uses about 80% RAID5, and 20% RAID 0+1... when in AutoRAID mode, it will automatically change RAID levels and other tunable items so that it does NOT treat your data all the same... for example, your redo logs will be treated differently than tablespaces, in a way that gives them better performance.

So, the others who responded to you are correct, don't worry about performance, because the array will automatically tune itself to give you the best performance.

Now, the VA 7400 has one other thing you should note - it has 2 redundancy groups. This means that there are really 2 sets of 0+1 drives in there. Specifically, it's every other drive - the drive in slot 1 is "owned" by controller 1, the drive in slot 2 is owned by controller 2, the drive in slot 3 is controller 1, slot 4 is controller 2, and so on.

When you create LUNs on the 7400, you will have to specify which Redundancy Group the LUN should go on - read this as which controller "owns" the LUN. You may get better performance by putting your redo logs on one controller (redundancy group) and your rollback segment on the other controller - separate them onto different sets of disks. Spread your tablespaces evenly across the controllers, too.

Doing this should give you the best performance the array can deliver.

Good luck!
No matter where you go, there you are.