March 21, 2014 at 6:54 am
I have read lot of articles and found out that it is not a good idea to use VM for Data Warehouse.
Currently, we are going through server upgrade and SQL upgrade (SQL Server 2012). Our server team recommended that we should move our environment on VM where he can give us our own Chasses to host the virtual servers and 5 virtual servers on it.
My current environment runs on physical servers.
I don't have much experience running data warehouse on virtual servers so I would appreciate if you guys can provide me any guidance. I dont mind if you send me link for any articles.
Thanks in advanced for your help.
March 21, 2014 at 7:09 am
I am not an expert at all, but we have been running SQL Server (currently Enterprise 2012) for a year or three under VMWare and we are very very very satisfied. No problems ever. When we need extra memory, storage etc. it could even be added during production hours if necessary. From my personal experience I would recommend running under VMWare.
March 21, 2014 at 10:05 am
Hi Raymond,
Thanks for your reply, our main concern is running ETL as we crunch lot of data. There is already a performance issue where we are fixing it. Plus, I am not sure how is your VM set up but how much competition for resources the VM will have - if they're multiple VM on same hardware.
What if the VM host goes down, all the VMs that it is hosting go down. With the physicial server you can (or hope to) manage it better.
Any thoughts..
March 21, 2014 at 10:10 am
VMs are pretty solid and work quite well. Just as well as physical machines these days if they're properly set up and maintained. But, performance could be an issue there because, no matter what, you're adding a layer of code on top of your operating system and SQL Server and your hardware. So, the biggest question is, how stressed are your current machines? Are they operating at 50% or more of capacity on a sustained basis? If so, going to VMs could be a very poor choice. If they're sitting there asleep most of the time, 25% or less sustained, the VMs and shared resources may not be a bad idea at all.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning
March 21, 2014 at 6:06 pm
the biggest problem with VMs is storage performance which for your DW you'll probably need. Virtual disks are generally good for standard sequential I\O but suck for random I\O. There are somethings that just shouldn't be virtualised. What are the specs of the VM hosts, what spec do you require for the VM? If it's anywhere near even close to a 1-1 then do not virtualise.
i.e. if the host has 64GB RAM and 4 socket 4 core CPU and you want to lend 32GB RAM and 8 vCPUs to the VM, i would say keep it physical.
There is an overhead from the hypervisor but if done correctly you can achieve excellent performance and reliability.
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"Ya can't make an omelette without breaking just a few eggs" 😉
March 21, 2014 at 9:39 pm
Perry, really? I've seen more issues with CPU and memory from VMs since those are the shared resources. Not arguing, just requesting more information.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning
March 22, 2014 at 12:36 am
Yes really, memory and cpu can be over committed usually without too much problem. If you follow the best practice and avoid over committing then cpu and memory will never be an issue anyway.
Getting the storage performance right has the biggest challenge and overhead. You only need to look at how a virtual machines virtual disks are comprised and then factor in the host storage throughput limitations and there will be some 😉
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"Ya can't make an omelette without breaking just a few eggs" 😉
March 22, 2014 at 12:38 am
keyun21 (3/21/2014)
Hi Raymond,Thanks for your reply, our main concern is running ETL as we crunch lot of data. There is already a performance issue where we are fixing it. Plus, I am not sure how is your VM set up but how much competition for resources the VM will have - if they're multiple VM on same hardware.
What if the VM host goes down, all the VMs that it is hosting go down. With the physicial server you can (or hope to) manage it better.
Any thoughts..
When using vmware HA the vms will be restarted on another host
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"Ya can't make an omelette without breaking just a few eggs" 😉
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