3 Argentium

RAID 1/0 configuration

Hi Gurus,

Will a 5+5 RAID1/0 configuration be optimal for a traditional RAID group (not the storage pool)?

I know that private RAID1/0 RGs in a storage pools require a number of drives that is equally divisible by 8, like 4+4. It does not apply to the traditional RAID1/0 raid groups though, does it?

Appreciate your input.

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4 Tellurium

Re: RAID 1/0 configuration

Hi, Best/preferred practice for Raid groups is also 4+4. But you'll still be able to create a 1/0 group with a 5+5.

When you create it and select your disks manually, if the drive count is invalid you'll see a msg like this. Otherwise you're ok.

inv_10.jpg

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3 Argentium

Re: RAID 1/0 configuration

Thanks Brett. So best/preferred practice would be 4+4, 8+8. Or I could do any combination, like 5+5, 6+6, 7+7? I know it has to be an equal number of drives, but cannot find any BP in EMC docs for this, apart from private RGs in Pool LUNs.

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4 Tellurium

Re: Re: RAID 1/0 configuration

That's right, multiples of 4 is preferred, and as a RG can only have 16 disks, a 8+8 is the max. The optimization for the preferred drive counts occurs only under certain conditions, and would not be a big difference, on balance to most workloads.

In short...go for it, if that's the disks you have

What you can consider is if you wish to expand (using meta's) in future. If this were the case you'd be advised to keep the counts the same for all components to ensure they perform consistently, IMO. This is similar to if you expand a pool.

You'll find a little more info under "Classic RAID Group considerations" in BP for Performance guide.

(attached)

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3 Argentium

Re: RAID 1/0 configuration

Thank you Brett.

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