VMware SQL memory limit/unlimited

[MrHoek]

Dear VMware users,

We have a problem with out SQL server and I have tried to find the solution in the server it self.
But unfortunately I couldn't find the solution, but we have a SQL server that keeps crashing like 3 or 4 times a week.  The error say's that the connection from our other server to our SQL Server is  lost.

Our SQL server has the current hardware configuration:

- Microsoft Windows Server 2008 R2 (64bit)
- 4 CPU's (Xeon X560 @ 2.67GHz)
- 10GB memory

In the SQL management studio I have set the memory to a max of 8096 MB, this is shown in the picture:

Since this didn't helped me on resolving this issue I'm trying to find the problem and solution in the VM it self.
Like shown above the SQL server has 10GB memory, this is shown in the picture:

When I now go the tab Resources from this server and then to Memory I can see that there is set a Limit on 4096MB. This is shown in the picture:

So what I know was wondering is the following:
Is the server now not using more then 4GB since we didn't used the option Unlimited.
And If I set the option Unlimited on, does this resolve my problem? I have also a picture which show's our Memory overview this picture is named:

What do I wish to hope
That the server has 10GB memory and the SQL uses 8GB from this and the server it self uses only 2GB (this is a configuration in the SQL management studio which I already have implemented).

I know that this my sounds not right, but I don't know were to search currently and our server is crashing.

I hope I have made my self clear and that with the help from you volunteers to make me realize of this is a good idea or not to set the option Unlimited on.

Kind regards,
Martijn

[MauroBonder]

Once you have limited memory, the virtual machine can not use more than that, the OS will not have the intelligence to know that you can get 2GB more or not.

I believe that if you leave without limitation and try to target the use through its application is the most correct, that if it supports this kind of customization, otherwise does not have much to do.

try read page 8 of this guide,   http://www.vmware.com/files/pdf/sql_server_best_practices_guide.pdf

hope help!

[MrHoek]

Dear MauroBonder,

Thank you for already replying so quickly, to answer you.

I have given the VM server 10GB memory and when I look inside the server it self it say's it has 10GB memory (System Properties).
And then when I look in the vCenter at our SQL server and the Properties from this VM it also displayed 10GB memory has been given.
But then when I go the Resources tab and go to Memory it show's it has a limit of 4096MB.

Does this basically mean the server will never use more then 4096MB aldo 10GB is given?

I know I have almost repeated my self but I want to know for sure that I'm not doing the wrong thing.

Thank you again!

Kind regards,
Martijn

[MrHoek]

Dear VMware users

I think I have answered my own question but if someone wants to reply that this is the right option I feel my self more safe.
Looking at the Resource Settings I see that we have Configured 10,00 GB but have put a lock on it by setting the Limit to 4,00 GB.

Is it now true that our server will not use more then 4GB aldo 10GB is assigned.

Kind regards,
Martijn

[MauroBonder · Accepted solution]

You´re welcome.

Setting limitation your vm never will use more than specified on limit.

I.E VM have configured 10GB, but with limitation of 4GB. This mean that your VM never will use more than 4GB.

Limit is the upper bound of the amount of host physical memory allocated for a virtual machine. By default, limit is set to unlimited,
which means a virtual machine’s maximum allocated host physical memory is its specified virtual machine memory size

[a_p_]

Is it now true that our server will not use more then 4GB aldo 10GB is assigned.

The limit is transparent to the VM and it will see the 10GB memory regardless of the limit you configured. However if the VM accesses more than 4GB, this will be swapped to disk by the Hypervisor.

André

[MrHoek]

Dear André & MauroBonder,

Thank you so much for answering this, it made my day!
So thumbs up for you 2 both!

Kind regards,
Martijn