New to VSA Questions

[Tom Lyczko]

I'm looking at this VSA for a "greenfield" vSphere cluster installation of two ESXi 5.5 host servers this summer.

We'll probably consider the 4TB 3-node bundle...each host server would get VSA installed to it.

The servers will be DL380s with 8 x 600 or 8 x 900 15k SAS drives.

I plan to set the hard drives in hardware RAID 6 once I figure out what HP controller I need.

If I use 8 x 600 15k SAS drives in RAID 6 in each of two servers, this would present about 3.5 TB total storage to the VSA, and combining the two hosts' VSAs in RAID 1 would be about 3.5 TB total usable storage, correct??

What happens if I use 8 x 900 GB 15k SAS drives in RAID 6 to the VSAs?? Would the VSAs just ignore the excess storage??

Is it better if I use 6 x 900 GB in RAID 6 and 2 x 1 TB SATA drives or something instead?? to get close to the maximum 4 TB per host?? (this would be like having two LUNs per host??, one of them being 3.5 TB the other 1 TB)???????

I do realize expanding the storage can be done by presenting NFS storage as well to the hosts.

Since this is a "greenfield" installation several VMs must be created, configured, etc. before the VSAs can be deployed. Am I correct in assuming that NFS storage should be temporarily used for this purpose until the VSAs can be installed to the host, after which the VMs (domain controllers, vCenter Appliance) on the NFS can be moved to the VSA storage??

Thank you, I hope my questions are not too difficult or confusing, I am learning as I go...

Thank you, Tom

[oikjn]

I can't comment on the best way to do the esx deployment, but unless you get the 10TB license that includes AO, you do NOT want to mix drive speeds in the same VSA.  VSAs only deal with their storage as raid0 so you have to have your raid done in the host OS or on the raid controller.  I don't know how tight you are for space, but I would probably just go with the 8x600 to get you the 3.5TB or even bump to raid5 to get the extra space if needed.  the double-disk redundancy isn't really needed when you also use NR10 unless you are really really paranoid  (HP uses raid5 for their physical nodes).

You are correct about the space usage, two 3.5TB nodes will give you a total usable space of 3.5TB assuming all your LUNs are done NR10.

Keep in mind that unless you have a THRID physical host to hold the FOM, you will not be able to ensure that you don't have to worry about SAN availability during a single-host failure.  It is a very small VM, so it can go on anything as long as it stays on.  I put it on our backup server at one site and on ourr one physical DC on another because I didn't have another option.  That DC is an atom processor and even that ran it fine!

[Tom Lyczko]

If I'm understanding you correctly, I should install the disk drives in RAID 5 with the DL380's physical RAID controller, then tell the VSA to do the two servers in NR10??

What is AO??

What happens if you have more disk space installed on the server than the license allows?? (e.g. the 4 TB license and one has 6 TB on the server??) -- does the VSA ignore the extra space??

Can I put the FOM on a partition separate from the VSA partition and run it locally on the host??

I read this article that seems to work around the FOM/third server issue:

http://vmfocus.com/2012/10/02/part-3-automating-hp-storevirtual-vsa-failover/

I ask because later after typing the initial message I remembered we may be getting DL380s with 12 LFF drive bays.

Thank you, Tom

[Bart_Heungens]

Hi,

Yes correct. First you apply RAID5 on the disk level in the RAID controller, than use that space in your VMware and create a VMFS datastore. On that datastore you will place the VSA files.

If you have a datastore of 6TB and you have a 4TB license, you will have the VSA using 4TB of the 6TB datastore, so you will keep 2TB free space on the local datastore (which is local storage and not shared storage). There is no space to ignore, the VSA will have a VMDK file of 4TB...

Finally on top of the VSA's you will apply NR10 which will create a shared storage volume on top of the multiple local datastores...

Regarding the FOM, ideally you should place it on a third/separate server. You can install it on the same server where the VSA is running (since you have local free space) but remember that, when that server running 1 VSA and the FOM dies, you won't have quorum/majority and so you NR10 volumes will stop I/O to the data. That physical server became as such a SPOF...

AO means Adaptive Optimization and is the subLUN tiering component inside the 11.0 version. If you have 2 types of storage in your server (SAS/SATA/SSD), than the VSA will put the 'hot' data on the fastest media and the 'cold' data on the slowest storage component.

Kr,

Bart

[Tom Lyczko]

Could one put a FOM on EACH VSA server??

Thank you, Tom

[Bart_Heungens]

Hi,

What do you mean with putting a FOM on each VSA? Because it doesn not work for that.

You should see the FOM as a VSA (so it is a virtual machine as well) but without any storage behind... So it does not participate in the NR10 story...

The FOM is there to avoid split-brain situations. This means that, if you have 2 or 4 VSA's in 2 locations, and you have a network problem between the 2 sites, that the FOM will decide for you which of the 2 sites will remain active (and so to avoid data corruption).

So you will have 2 servers with VMware or HyperV, install 1 VSA per server on the local storage and besides that you will need the FOM. Yes you can install the FOM as a third virtual machine on 1 of the 2 of these servers, in parallel of the VSA on that same server.

And like I mentioned in my previous answer, ideally you install a third (separate) server for the FOM. If this is not possible you can place the FOM on the same physical server as where the VSA is running but you should know that, if that physical server dies, the FOM and the VSA will die, which means that you don't have majority anymore (2 out of 3 are gone) and so you will loose data access.

That is why it is better to have the FOM on another machine...

I have many customers that activate the FOM on another server like the backup server or whatsoever...

Maybe check also my blog post on Network RAID. I mention also a little the reason of the FOM in the NR10 story...

http://www.bitcon.be/?p=2537

Kr,

Bart

[Tom Lyczko]

My phrasing was taken too literally.

I meant put a FOM on each server's local storage separate from the VSA appliance/datastore.

I also realized I can put the FOM onto separate NFS storage accessible to both host servers, the NAS is local backup storage anyway.

The server room has UPS protection and generator failover for power outages, the most likely issue.

Thank you, Tom

[Bart_Heungens]

Tom,

Know that you should install only 1 FOM in the storage cluster, to create an odd number of nodes... If you would have 2 VSA's and 2 FOMs, I have 4 nodes which gives you again a possible situation where you have 2 + 2 nodes and so no majority.

Best practice of HP is having 3 or 4 so called 'managers' so 2 or 4 VSA's and 1 FOM...

And yes that FOM can be on the local storage of the server or on a separate NFS volume...

Kr,

Bart

[Tom Lyczko]

OIC :) Thank you for your help so far!! I don't know yet if I will install it or get help from HP...I will ask here about tuts etc. after I check HP's videos...I have the laptop trial bits.

[Bart_Heungens]

Installation should be quite easy...

VSA's can be deployed with the Zero-to-VSA deployment tool.

After that install the CMC (next-next-finish) and follow the wizard...

First do a discovery of the VSA's, create a Management Group, create a cluster and finally create volumes...

Couldn't be easier...

Kr,

Bart