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Merge HP EVA4000 SAN

 
SMaxwell1
Occasional Contributor

Merge HP EVA4000 SAN

Hi All,

We have two HP EVA4000 SAN's and I'm looking at the possibility of mergeing them as we will be bringing them both under one roof.

The one has 4 x shelves and 56x300GB FC-AL Disks and the other EVA4000 has 3 x shelves (28 x 500GB FATA + 4 x 1TB FATA).

I appreciate we will need to do some upgrades; however this is where I'm looking for advice.

Is this possible? Will we have to backup/Restore data if we merge, etc?

Cheers
9 REPLIES 9
Uwe Zessin
Honored Contributor

Re: Merge HP EVA4000 SAN

An EVA4000 can address up to 4 disk drive enclosures. If you want to connect more, you have to upgrade to an EVA6000. That means the introduction of loop switches in the disk back-end with a complete recableing and you need license upgrades (unlimited EVA4000 to unlimited EVA6000).

You cannot do a meta-data merge of two EVAs. You do have to save the data of one system on external media. Be VERY careful and do not introduce disks from a second system while the first one is not running as the controllers might get confused by duplicate meta-data information.
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SMaxwell1
Occasional Contributor

Re: Merge HP EVA4000 SAN

Thanks for this. How many shelves can a 6K support? I read somewhere it's 12, but wanted to confirm?

Cheers
Uwe Zessin
Honored Contributor

Re: Merge HP EVA4000 SAN

An EVA6000 supports a maximum of 8 disk drive enclosures (=8*14=112 disk drives).

If you need more, you (would) have to upgrade to an EVA-8000, which can address 18 enclosures. But: it requires a new set of controllers, another pair (=4 total) of loop switches and: guess what? A new set of licenses.
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Mark Wibaux
Trusted Contributor

Re: Merge HP EVA4000 SAN

Any particular reason you really need to merge them in to one set of controllers?

Why not just run them in the same fabric, one CV server will be able to manage them both. You have different disk types in each so it's not as if you can merge the disk groups.
By leaving them separate you have the performance benefit of multiple controllers, multiple host interfaces etc.

One thing you won't have is the ability to snapshot from one disk type (FC) to another type (FATA).
One things for certain, upgrading the controllers to 6000 or 8000 spec along with licenses, support, downtime etc is not going to be cheap.

Oh just out of interest, what protection level are you running on the diskgroup with your FATA drives in it?
AlexatHP
Occasional Visitor

Re: Merge HP EVA4000 SAN

I agree that you probably don't want to do that. EVA is a midrange storage array, by mid-range, I mean, we don't want to put too much work load on one pair of controllers. By using them as 2 seperate EVAs, you can still easily put them into same fabrics and easily manage them by using one commandview interface.
EVA controllers are very expensive. For better performance and better availability, I believe keeping them seperate is better.
SMaxwell1
Occasional Contributor

Re: Merge HP EVA4000 SAN

Thanks for the replies folks. I was looking at it from a rackspace point of view; we're merging our data centre and was looking to keep the number of racks used to a minimum.

Will look into using the one fabric; any gotcha's we should be aware of when we contemplate this task?

Cheers
SMaxwell1
Occasional Contributor

Re: Merge HP EVA4000 SAN

@Mark

When you say protection level; Do you mean "Disk Drive Failure Protection" ? If so, that's currently set to Single.

Cheers,

Mark Wibaux
Trusted Contributor

Re: Merge HP EVA4000 SAN

Yeah that was the bit I was referring to.
The reason was that you have a mixed sized disk group for your FATA drives. If you set your disk protection level to single then the EVA reserves twice the capacity of the LARGEST drive in the disk group. Double protection reserves four times the capacity.
Hence if you had set yours to double protection prior to adding the 1TB drives to the 750GB drives your reserved protection space would have jumped from 3TB (4 x 750GB) to 4TB (4 x 1TB).
It's really only a concern if you add 1 or 2 larger drives to an existing Disk Group (and also the amount of difference in capacity between the smaller and larger drives). It's actually possible to end up getting less space in a Disk Group by adding a larger capacity drive to it.
Mark Wibaux
Trusted Contributor

Re: Merge HP EVA4000 SAN

Oops I should have looked back up the beginning of the thread. You have 500GB drives in with the 1TB ones. So that just makes the jump in capacity lost to protection level that much more.
Again with Single protection in your case probably not that big a deal.