HPE StoreVirtual Storage / LeftHand
cancel
Showing results for 
Search instead for 
Did you mean: 

Storage location for VSA Virtual Machine on ESXi Host (P4000)

squirrel_SCK
Occasional Visitor

Storage location for VSA Virtual Machine on ESXi Host (P4000)

Hi,

 

i am in a project where we have two DL380pGen8 Server with each 13 x 300gb Hdds.

We want to use P4000 as storage system.

 

Disk 1 + 2 (Raid1) are running the ESXi.

 

Disk 3-12 (Raid10)  are intended to be one volume for VSA-Store --> here will ten other VM be stored

 

Disk 13 Hotspare

----------

 

So now i come to my question. I read the HP VSA Documents but there is a little confusion about that:

The documents are saying "The VMFS datastore or NTFS partition for the VSA must not be shared with any other VMs."

 

What is this meaning exactly?
 

I have deployed the VSA VMs and the FOM  on the same Volume with ESXi (Disk1+2)!

Is this a fault?

Should i deploy the VSA VMs to the same Volume where later on the VSA will have its Storage Volume?? (disk 3-12)

 

 

We are completly new to this virtual storage topic. May someone help us in our confusion? :-)

 

Thanks and Greets

 

S.C.K

8 REPLIES
oikjn
Honored Contributor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

It might sound dramatic and the VSAs will definitely work while using storage that is shared by others VMs, but the requirement for providing exclusively dedicated drives is purely for support.  Since the VSA's performance is directly impacted by its underlying storage and that storage is directly impacted by all VMs accessing said storage, you cannot put any other VM on the same storage if you want to make sure the VSA performs consistently as it is supposed to. 

 

You could (and I do) put other VMs on the same storage as the VSA, but I know that if I have a performance problem that would require me to go to HP to fix, the first thing I'll have to do before going to them is remove all other VMs from that storage and make sure the problem is still there.

5y53ng
Regular Advisor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

What you described will work fine. If you want to gain a little extra capacity from your setup you could RAID 5 or 6 all disks as a single array, configure 2 logical disks, say 150GB to host ESXi and the VSA, then allocate the rest of the storage to a second logical disk to provide storage to attached to the VSA.

 

Using RAID-10 on the physical array and then Network RAID-10 for the VSA sacrifices a huge portion of your capacity.

Sbrown
Valued Contributor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

svmotion/migrate the other vm's off.

What you have is a timesharing problem since raid cards do not support SR-IOV.

Every device that has to share will incur penalty for QOS. Which is why the FC/FCOE guys came up with SR-IOV and virtual FC/FCOE so the server sees a dedicated nic and the chipset deals with it.

Simple test - put 1 vm on a single box. watch peak SAS and NIC performance.

Load up two or three vm's watch the performance plummet even if the other vm's are not doing much.

If you can afford a second nic,raid controller, socket you can isolate the VSA to its own gear, there will be little to no contention.

Remember the LSI SAS is 16 QUEUE DEPTH MAX! PVSCSI is 32 but (in windows) can be set to 255 (Per lun/target).

It is very likely that 5 scsi devices (raid-1) will outrun 1 large raid since the queue depth can be realized - but if the o/s is limited to 16 or 32 QD you will have a hard time pushing the raid controller. IIRC the P410/P420 can do 900 queue depth in ESXi but one VM will be stuck at 16 (LSI SAS) to 32(PVSCSI) per target.

Without pushing 64 QD per SSD - a lefthand VSA would never realize peak SSD performance. This is why folks layer 2 or 3 VSA's and use multiple scsi targets (5 raid-1 is way faster than 1 RAID-10 with ssd).


vm (16 QD) -> ESXI (940QD -> Luns (0-64QD) see the problem here?
squirrel_SCK
Occasional Visitor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

Thank you all for your replies!

 

I think i understood the issues you mention.

 

I am going to change my setup to the following:

 

----------

Disk 1 + 2 (Raid1) are running the ESXi + the VSA Machine

Disk 3 + 4 (Raid1)  Volume1 for VSAStore

Disk 5 + 6 (Raid1)  Volume2 for VSAStore

Disk 7 + 8 (Raid1)  Volume3 for VSAStore

Disk 9 + 10 (Raid1) Volume4 for VSAStore

Disk 11 + 12 (Raid1) Volume5 for VSAStore

Disk 13  Hotspare

----------

Then i add the five Volumes to my ESXi Hosts.

Then i add the five "Disks" to my VSA.

 

VSA then can work like before but the Hardware Raid Controllers will use the hardware capacity.

 

Then i have many Raid-1, and via the VirtualRaid-10 from VSA i have Raid 0 functionality over Network.

 

Right???

 

Please correct me if i'm wrong!!

 

 

 

And to Reply to "": ..."Using RAID-10 on the physical array and then Network RAID-10 for the VSA sacrifices a huge portion of your capacity."...

 

As i understand, in the VSA Documentation it says "...Use redundant RAID for the underlying storage of a VSA in each server to prevent single disk failures from causing VSA system failure. Do not use RAID 0...."

 

So the only way to get more storagespace from my hardware would be to Set my five Raids as Raid-0 and then get the Raid 1  from the NetworkRaid. But this would violate the statement in the manual.

 

 

 

Greets S.C.K.

5y53ng
Regular Advisor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

Hi,



I suggested you use one disk group/array in a RAID5 or RAID6 configuration, not RAID 0. I'm skeptical that individual sets of mirrors will outperform a stripe of all your disks.
squirrel_SCK
Occasional Visitor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

Ok, i thought (with regards to Sbrowns post)  this approach would be the better way.

 

Hmm t think i will do a performance Test.

 

...

5y53ng
Regular Advisor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

Keep your capacity requirements in mind as well as performance. For example using some approximate numbers;

 

With 2 hosts and 13 x 300GB disks each:

 

Using five RAID-1 disk groups with a hot spare, your approximate SAN capacity is 3000GB (1500GB per host, or 10 x 300GB / 2)  You are allocating 600 GB (2 disks)  to host ESXi (5GB in size roughly) and the VSA (about 7GB in size, thick-provisioned) Note that you cannot add a sixth VMDK to the VSA to recoup the additional storage on the mirror hosting ESXi and the VSA VM.

 

Now, add the Network RAID-10 of the VSA into the picture and your usable SAN capacity is 1500GB.

 

If you configured all your physical disks as RAID-6 and create two logical disks, say 150GB for ESXi and the VSA, then allocate the rest for the VSA datastores, your SAN capacity is now approximately 6200GB (3150GB per host)

 

Factor in the Network RAID-10 of the VSA and you're at 3150GB total capcity.

 

That's a significant difference, 3TB vs 1.5TB.

Sbrown
Valued Contributor

Re: Storage location for VSA Virtual Machine on ESXi Host (P4000)

Doesn't matter how much storage you have if it is too slow.

Squirrel - let me know when you see the datastore latency warnings on the VSA :) give that big raid-6 a shot and tell me about the message that follows a few datastore latency warnings.

LATENCY.

I'd strongly strongly super-strongly suggest running 1 guest per host - as a baseline.

Once you add another VM guest to that adapter, let us know how performance changes. VSA+1 or more vm's versus only VSA.



We're talking random i/o - not linear benchmarks.

I do not advocate unsupported configurations for production, but to ensure you have a solid baseline for performance. Some people just use broad math. I suggest using real-life benchmarks.