P4500 Basic Storage Config

[Dooley do]

Hi,

I am looking to deploy a 14.4TB P4500 virtualization solution to virtualize a load of servers on our network. This comes with two nodes.

I am going on the course soon but I am interested to know what the best practice is for storing VMs and data on these systems. For example, with physical servers for Exchange I would use RAID 1 for OS and logs and RAID5 for data. How does this translate to the P4500? Is the whole thing set up as a massive RAID5 and then the raid1 drives I need then are "virtual" raid1 sitting on raid5?

I am interested in using network raid in case one of the nodes fails completely. Is this a good idea or are they so redundant that it would be a waste of space?

I am in an SME with and I am looking to have approx 12 VMs running on this setup.

Thanks

[Steven Clementi]

The nodes themsleves have a raid array and the disksare likely configured in 1 of 2 configurations... depending on how many disks you have per box.

1 array, 1 logical drive: RAID5
2 arrays, 1 logical drive each: each RAID5

This is changable via the Lefthand CMC. Probably not something you want to change though.

Each node has physical storage that gets added to the cluster. From the cluster, you can configure various volumes with different settings. Most notably, Network RAID.

If you are goign to use Network RAID, keep in mind that you have up to half you available storage for a single volume (or set of volumes) since you are basically mirroring your data (in a 2 node configuration).


Since you are using virtualization, the virtual machines don't really care about RAID level.. they can't even see it. You simply present a volume to your virtual host, then carve up space out of it to create your virtual machines.

Which technology are you using...VMware? Hyper-V? Zen?

Without network raid... the boxes are not redundant to each other. They simply act as a pool of storage.


Steven

[teledata · Accepted solution]

My general advice would be to leave the harware RAID5 on the nodes (as they came pre-configured). And use Network RAID 10 (2-way replication) for your volumes to provide a highly available datastore for virtualization.

If you choose Network RAID 0, you will LOOSE access to your storage if a single storage nodes goes down (reboot, failure, software patching or any other reason). So if high availability, and the luxury to perform maintenance on your storage nodes without taking your VMs offline is of importance, then stick with Network RAID 10.

Like the previous posted noted you will consume twice the storage cluster capacity.

Here is a capacity calculator that you can use to show your usable storage based on different replication scenarios:
http://www.tdonline.com/hp-lefthand/storage-calculator/

[Dooley do]

Great, thanks for your input. Can I designate some of it to be network raid10 (ie for critical apps like exchnage and sql) then not use network raid for things like the development and test environments?

Thanks

[Steve Burkett]

Yes, the Network RAID is defined by volume, so you could have your Exchange data volume using a different Network RAID type to say your test SQL Servers data volume or your VMWare datastore volumes.

Concur with Teledata on the 'stick with the RAID5 on the nodes themselves and go with Network RAID 2 (mirroring) for protection against node failure' advice. This is what our consultant from HP UK went with for our install.

Because you've got the higher spindle count and multiple controllers, it sort of negates not having dedicated RAID 10's for your Logs like you would in direct attached storage.

[Dooley do]

Great, should be quite easy then. I shall be using Hyper-V with CSV. For exchange and SQL I will use the network raid, for some of the less important stuff I will not.

For exchnage/SQL is it still recommended to create 3 volumes (OS, Logs, Data) even though they will actually just be all in the same place?

Thanks

[Uwe Zessin]

Absolutely!!
If somebody accidently remove one volume or a file system becomes corrupted you still have a chance to recover the database without much loss of data.

[Dooley do]

Great, I am going on the course in a few weeks so this is a very good start.

[Paul Hutchings]

Don't forget that you have 100tb of VSA licenses with the P4500 Virtualization Bundle which lets you do some funky stuff with your old or underutilized ESX/Hyper-V servers.