MSA1500 + VMware - how many VMs do you run?

[raadek]

Hi all,

Yes, I know the MSA1500 is an entry-level box & EVA is better suited to run VMware. But as customers are more and more cost conscious these days...

Can you share with me your practical experience stating a number of VMware virtual servers you happily run off the MSA1500?

All answers much appreciated (& rewarded with points).

Rgds.

[Patrick Terlisten]

Hello raadek,

I think that the number of VMs will depend on the number of disks and the used raid level. The MSA1000 controller can deliver >30.000 IOs/s. IMHO is the number of disks an the 2G host connect the limit. I know an enviroment in which the customer uses 15 VMs on two DL585.

Regards,
Patrick

[Steven Clementi]

I agree.

Also to take into consideration... how big of an OS / Data partition do you need for each VM? Sure, the MSA1500 can utilize up to 56 300GB drives... that should be plenty of space to build hundreds of small VM's. (4 shelves * 56 disks /2 (for RAID1) /12 (for OS disk) = @640 VMs with a 12GB OS disk) (just an example)

Another thing to consider is the amount of VM's you actually want to run on each server and what applications are runnning on each VM.

I can have 64 VM' that do absolutely nothing but run an OS and I doubt I would have a problem. Take the same 64 vm's and drop heavily used exchange services on them and BAM! you have yourself a potential problem. (again, just an example)


Steven

[Patrick Terlisten]

Hello,

think about the 32 LUN limit. :)

Regards,
Patrick

[raadek]

As written in my first post - I am aware of the MSA1500's limitations.

32 LUN limit is not that significant in VMware implementation, because you can keep all virtual disks within one LUN. That's the catch I overlooked some time ago saying to Mr Customer that it's not possible to keep more than 32 VMs on the MSA1500 (which is not true).

And yes, I understand that different VMs have different performance requirements.

That is why I asked you to share with me REAL LIFE examples (ideally from a production environment).

Rgds

[John Kufrovich]

raadek,

It really depends application and the load on the MSA. If properly tuned, the MSA can handle quite a bit. The main thing to keep in mind is not to let the controller be the bottleneck. If it gets to that point, then all servers will backup.

[Uwe Zessin]

How can the controller become a bottleneck and how do you "tune" it?

Isn't it supposed to be able to do around 30,000 IOPS? That's more than 500 IOPS per disk in a fully loaded system.

[John Kufrovich]

>How can the controller become a bottleneck >and how do you "tune" it?

Answer: If the controllers cache is 100% utilized or reached max. Queue for the controller. You can tune it by making changes to MSA LUNs. Changing stripe size, drive count or workload distribution.

>Isn't it supposed to be able to do around >30,000 IOPS? That's more than 500 IOPS per >disk in a fully loaded system.
Yes, but at what block size. The whole storage industry quotes Maximum IOPS or MB/s.

[raadek]

Just to move the thread to the front again: any REAL LIFE examples you can / want to share?

Thanks.

[Rmitchell_1 · Accepted solution]

Raadek,

My company has been using the MSA 1500 with VMware for alost a year now. We actually have two and we are very pleased with the results.

Our hardware -
3 DL385 hosts (ESX 2.5.3) connected per MSA 1500. MSA 1500 dual controllers, 512 cache, 4 shelves with 146GB 15k Drives. Brocade 32/4 switch. Active/Passive firmware..5.02 and 5.10

Our Config - Each MSA has 4 arrays. ArrayA is RAID 0+1 and ArrayB-D is RAID5. ArrayA has 3 200GB LUNS meant to only hold OS drives. ArrayB-D has one 200 GB data LUN on each to hold DATA Drives. The rest of the space is for Raw Disk Mappings(RDM). We use the RDMs for our file server data drives and SQL server data/log drives. We use SSP and Zone the switches.

Design Considerations:
1. Build Arrays Virtically. Since we have 4 Shelves, Each array will be spread across all four.
2. Split OS and DATA drives. We put our OSs on the RAID0+1 VMFS LUNS and the data on the RAID5 LUNS (VMFS or RDM)
3. When formatting VMFS drives for ESX make sure you align the partitions w/ FDISK.
4. When formatting the DATA drives for your Windows data drives, align the partitions with diskpart.exe
5. When using SSP, set the connection type to LINUX.
6. Only use 2 procs in a VM if necessary.

Our Experience - So far things have been great. We have virtualized roughly 15% of our data center...about 50 servers...25/msa. This includes our file servers, domain controllers, some SQL servers, citrix servers and web servers. At this point we have not seen any performance problems.

One last thing. The VMware forums are awesome when it comes to getting questions answered. But they will trash talk the MSA.