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Re: How to setup Raid 10 array

 
Ian Burnell
Advisor

How to setup Raid 10 array

Hi

New to this forum and I'm not a server expert hence the question. I use Microsoft SCCM which uses SQL as its database and I've been told Raid 10 is the way to go. From what I've googled it appears that Raid 10 is just a stripe of Raid 1 (mirror) arrays. Therefore how would I set it up on a DL380 lets say for example. Assume there are 8 bays, Is it just as simple as saying 4 pairs as a C,D,E and F volume ?. What is the redundancy on this i.e can two disks go down (not in same mirror) and the system still work ok

Also can you mix and match disk sizes e.g. 36gb for O/S and bigger for data drives ?

Thanks !
3 REPLIES 3
gregersenj
Honored Contributor

Re: How to setup Raid 10 array

Yes, RAID 10 is a stripe of mirros.
You can create a RAID 10 with any even number of drives, that the array controler can handle.

When you create a RAID you do 2 things.
1 create an array or more arrays
2 create a LUN or more LUNs
You can create multible LUNs on an array.
You select the RAID level when you create the LUN.
LUNs can use different RAID levels within the same array.

There's to ways of configuring a Smart Array.
1. ORCA, Hit F8 when prompted during post.
2. Use the ACU, You must run it from the Smart Start CD, or from a runnig O/S.

The ORCA is simple at very easy to use, but with the orca, you can create only 1 LUN within an array, and it will use all the space within the array.

In your case you must use the ACU.
Create an array, using all the disks you want.
Create you LUNs 1 by 1, selecting the size you want.

Note
With the smart array, and multible LUN's on an array you will be able to extend the last (Upper) LUN only.

As you write, If both Disks fail in the same mirror, everything fails.
If multible disk failure occour, 1 in each mirror, you can survieve 50% loss.

I will recommend you to read the user guide for the generation 6 smart array.
ei. for the SA6i. It's very good

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Ian Burnell
Advisor

Re: How to setup Raid 10 array

Thanks for the reply.

So in my example if I have 4 pairs of disks then using ACU you could setup Array 1, 2,3 & 4. Do I assume that the LUN is effectively the partition size?. If the disk is 72gb then you setup the LUN to be up to 72gb

When this is done are these arrays effectively separate spindles. The recommendation is to install SQL and SMS onto different spindles which is why I'm interested in this

gregersenj
Honored Contributor

Re: How to setup Raid 10 array

Ahh you need it to be on seperate spindels.

An Array is like a "physical disk".
And the LUNs is the "patitions"

The real physical disk, can only be a part of 1 array.

If you got 8 disks, and want to use RAID 10, then all 8 disks will be in 1 array.

I do believe, that when you create the LUN's, you will have to select wich physical disks, the LUN will use (I'm not 100% sure, it's been a while, since I have done that).

I don't know what will give you the best performance a RAID 10, using 8 disk, with 4 LUN's, or 4 Mirrors, 1 LUN each.

Beware, when you work with Smart Array, HP still call it RAID 1+0, when you create a Mirror, and Compaq used to call RAID 10, 0+1.
Still if you select 2 drives you will get a RAID 1, If you select more drives you will get a RAID 10.

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