p4300 expansion

[mello_andrea]

Hi all

We have a new P4300 starter san solution with 2 shelfs in raid 1 of 8 hard disks x shelf SAS 15k rpm 450 GB.

We want to upgrade the storage to increase storage size and our supplier propose us to buy 1 shelf with 8 disks  SAS 7.2k rpm 1 TB.

But.....is this the best solution?? Add a new shelf with different disks performance, can impact in the total storage performance?? Or the new shelf can be manage separately from the other.

An hp installer suggest us to buy a new shelf with the same specifications of the other shelfs and create a replication level 3-way on the volume using network raid 5.

What is the best solution to not affect performance??

Thanks in advance

Andrea Armellini

[Bart_Heungens]

Hi,

This is indeed not an ideal situation...

Best solution is to go for the same drive with the same speed...

Kr,

Bart

[Paul Hutchings]

The simple answer is add additional nodes that are identical to the ones you have right now, however I would look at all the options and considerwhether you are expanding because you need performance or capacity, or both.

HP have some "interesting" pricing on single nodes which means that often it's as virtually the same to simply buy another bundle as it is to buy a single node.

Also keep in mind that the 450gb SAS SAN uses 15k drives - it's made for performance not capacity, and as a result if all you want is some bulk storage it may not be sensible and you might want to consider the MDL SAS systems which will give you a lot greater capacity at the expense of performance.

[mello_andrea]

Thank you for your answer.

We don't need performance, we need capacity, for backup and for virtual machine with not great IOPS impact (like antivirus console....) and a single MDL SAS expansion should be the best solution. But I must be sure, that the new node not impact in performance of the others.

The P4300 allows me to manage new node separately? I attach a slide that represent what i'd like to do, but i think it's possible only if I buy new bundle, and not single node, correct?

[Paul Hutchings]

You'd typically set it up as a second cluster with its own VIP.

What we have is one management group, and two clusters.

One cluster is P4300 MDL SAS, the other cluster is P4500 15K SAS.  Each cluster has its own VIP.

If all you want it bulk storage you could look at the VSA, I would certainly consider it as you could buy a pair of VSA licenses and install it on a pair of commodity servers for less money than I expect you'd spend on a single physical node.

Do keep in mind of course that the VSA performance won't be the same as the P4300, but it's something to consider when you look at your options.

[Bart_Heungens]

You can create a second cluster with just one node with MDL SAS drives... Off course when the node goes down, your volume is down... Raid 0 remember? If you have 2 MDL nodes in the second cluster, you can create Raid 10 so 1 node can fail, the volume stays online... Off course the cost per GB is higher...

Kr,

Bart