May 29, 2014 at 7:01 am
Hi community,
Some people, reject the idea, of running his production sql server in an virtualized environment, what do you think about this option and how can I overcome this opinion ? or How can I add more fuel to the fire ?.
Both options are valid
Thanks for your ideas.
May 29, 2014 at 7:41 am
It's dependant upon the machines requirements. For example if you have a host server with 64GB RAM and 16 CPUs and you require the VM to have 32GB RAM and 8vCPUs you could well argue that it should really be a physical server in the first place.
Storage requirements should be carefully considered too as this tends to have the highest overhead in virtual environments
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May 29, 2014 at 7:53 am
A lot of it boils down to resource requirements and how you configure the VM.
To convince people one way or the other requires a bit of a dog and pony show. Show them how performance will (or won't) be in the VM and then let them make up their minds from there.
If you configure resources adequately in the VM you will usually be ok (e.g. match the VM resources to the expected needs or the current physical box resources). Occasionally you will find that it still isn't up to snuff and you just need to go physical.
Jason...AKA CirqueDeSQLeil
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May 29, 2014 at 10:45 am
This all depends on the spec of the Production machine in my opinion. If the machine requires a small number of CPUs and a low amount of RAM, it may be worth virtualising.
However, if the server requires over (say) 8 CPUs and 32GB of RAM I would keep it physical.
Andrew
May 29, 2014 at 10:57 am
DBA From The Cold (5/29/2014)
This all depends on the spec of the Production machine in my opinion. If the machine requires a small number of CPUs and a low amount of RAM, it may be worth virtualising.However, if the server requires over (say) 8 CPUs and 32GB of RAM I would keep it physical.
Andrew
A VM with 8 vCPUs and 32GB RAM is perfectly fine if the host is well specced. But if youre going to assign a large portion of the host resources to a VM, it quite possibly should be a physical box in the first place.
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"Ya can't make an omelette without breaking just a few eggs" 😉
May 30, 2014 at 1:26 am
Perry Whittle (5/29/2014)
DBA From The Cold (5/29/2014)
This all depends on the spec of the Production machine in my opinion. If the machine requires a small number of CPUs and a low amount of RAM, it may be worth virtualising.However, if the server requires over (say) 8 CPUs and 32GB of RAM I would keep it physical.
Andrew
A VM with 8 vCPUs and 32GB RAM is perfectly fine if the host is well specced. But if youre going to assign a large portion of the host resources to a VM, it quite possibly should be a physical box in the first place.
Agreed, this topic is a massive "it depends". I guess I should have said it all depends on the spec of the host and then the spec of the server.
May 30, 2014 at 1:26 am
Unless you're pushing the outer bounds of what large hardware is capable of, the days of easy rejection of virtualization are over. In fact, I'd say, in most cases, virtualization makes more sense rather than less. SQL Server doesn't play well with others, but, once isolated off, it frequently doesn't use all the resources available to it. Putting it into virtual machines just makes sense.
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June 2, 2014 at 5:02 am
There are a number of well-known businesses that run their entire public-facing web site in the cloud. Virtualisation can and does work well for SQL Server when you use the right specification for the guest machines.
Most people know of big businesses such as https://www.netflix.com that run their entire public site in the cloud. Smaller businesses such as http://www.totaljobs.com/ are also 100% cloud hosted and are very happy with how SQL Server performs in this environment.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
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June 3, 2014 at 1:06 pm
Our environment is 80% virtual (550+ SQL server instances).
A previous point alluded to about SQL Server not playing well with 'others' is just not true.
SQL Server does not like having CPU and RAM resources given/taken away in the VM environment due to 'over allocation' - they have to be 'static' for SQL virtual servers. However the VM ESX host does not have to be dedicated to just SQL Server, you can mix and match Citrix, WEB, Application and other servers and 'over allocate' CPUs and RAM for those specific types of servers since they are far more tolerant of this type of resource give and take in the background. 'virtualization' can handle some really, really big stuff these days.
The present VM/ESX environment we have in place we maxed out a 'virtual' SQL Server at 16 CPUs and 64 GB RAM.
Our next ESX upgrade coupled with additional infrastructure late this year/early next year will allow us to increase that to 32/64 CPUs and 256/512 GB RAM per virtual SQL Server. With this type of VM infrastructure we can even even absorb our now physical HP DB-580's !
However, there still needs to be a 'solid' SAN storage infrastructure to power bigger virtual SQL Servers and TB sized databases.
Oh, don't forget the dual homed 10 GB NICs and a 10/100 GB backbone needed for the ESX hosts themselves as well !
The only other issue performance tuning. VM ESX has its set of tools, Windows and SQL Server have their own set of tools. Unfortunately there is what I'll call a 'translation gap' in between them. On extremely visible, heavy hitting systems there is a definite need for 3rd party monitoring software that can bridge the gap.
RegardsRudy KomacsarSenior Database Administrator"Ave Caesar! - Morituri te salutamus."
June 4, 2014 at 6:49 am
Rudy,
Do you ever have problems with vCPU wait times(I hope that is the correct term) since you're allocating so many CPUs to your SQL Server? Our VM guys suggest limiting the number of CPUs for our SQL Servers to 2 so the VM doesn't have to wait as long for the vCPUs to be available.
Andy
June 4, 2014 at 9:45 am
Not at all since our SQL VM instances have resources that are fixed.
We only 'over provision' WEB, Citrix and aplication servers - NEVER SQL Servers.
RegardsRudy KomacsarSenior Database Administrator"Ave Caesar! - Morituri te salutamus."
June 4, 2014 at 10:11 am
Rudy,
Thank you for the reply.
Andy
June 12, 2014 at 2:33 pm
Of course, once again...it depends.
Studies performed by VMware have shown that SQL performs from 88 to 99 percent as fast as physical under virtualization, provided that the host has CPUs that handle second-level address translation. And I do believe that this SLAT technology is what really tipped the scales in favor of virtualization.
Assuming the worst, the 12% hit is the equivalent to the passage of ~2.5 months under Moore's law. This leads me to argue that if your VM SQL server isn't fast enough in June, then your physical one wasn't fast enough in March. So, my approach is to assume the best and figure out how to fix things if my assumptions come up short.
I've had mostly positive results with virtualized SQL on modern hardware, whether using VMware, Hyper-V, or XenServer. Some exciting technology for backup and DR is available only to virtualized guests. (Veeam and Zerto to name a few) Sometimes the business will have reasons other than performance for choosing to virtualize.
Good luck and happy tuning!
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