Oversized VM's Report Too Agressive

Management reporting and documentation

Re: This can't be right?

Veeam Logoby chris352 » Sun Dec 23, 2012 7:20 pm

I think this report is wrong. the 11th VM down from the top has 8.00 GB ram allocated to it, is running Exchange server 2012 to over 200 people and I'm supposed to allocate only 1.9GBs of ram to it? How can that be correct?
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Re: This can't be right?

Veeam Logoby Vitaliy S. » Sun Dec 23, 2012 7:29 pm

Unfortunately, this report doesn't have any insight into the applications running inside your VMs, it is calculating the recommended amount of memory based on the memory usage (memory active/memory granted). Can you please open Monitor Client and see what amount of RAM your VM is actively using? Also I guess only Exchange and SQL Server VMs are affected by this, right?
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Re: Oversized VM's Report Too Agressive

Veeam Logoby murdocmk » Wed Dec 26, 2012 4:58 am

I wonder what the timer is for dropping pages from the active memory list? If it's aggressive, then I can see how that might result in misleading active memory counters.

I've looked but haven't found an answer to that yet.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby deduplicat3d » Fri Dec 28, 2012 7:05 pm

I'm assuming it is Mem.SamplePeriod, which defaults to 60 seconds.

http://pubs.vmware.com/vsphere-4-esx-vc ... butes.html

I would be careful about changing it as it appears to be used for several pieces of memory resource management.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby cparker4486 » Thu Feb 14, 2013 5:44 pm

I came to the forum having the same concerns. The ideas being presented here are hard to stomach but it certainly makes sense: regardless of what Windows believes it's using, the virtualization host knows the truth.

I'm going to setup some new RD Session Hosts and I think I will begin their RAM life at the currently recommended amount by the oversized report (for my existing single host).
-- Chris
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Re: Oversized VM's Report Too Agressive

Veeam Logoby ky-lab_rat » Fri Apr 26, 2013 5:50 pm

I'm seeing the same thing as the others have with the Oversize Report. Veeam is reporting that I need to downsize one of my VM's on memory. I circled the vm in the image below and the next image is a grab from veeam performance page showing that I should probably add ram and not remove it.


Image


Image
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Re: Oversized VM's Report Too Agressive

Veeam Logoby Vitaliy S. » Sat Apr 27, 2013 12:27 pm

The sub-report shows you memory consumed, not memory active. Can you please tell me what type of server is this? Is it a SQL Server?
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Re: Oversized VM's Report Too Agressive

Veeam Logoby ky-lab_rat » Mon Apr 29, 2013 1:00 pm

This is a centos linux vm running mysql. If that's the metric veeam uses then shouldn't that be mentioned or listed in the report it gives to validate the results to the user.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby Vitaliy S. » Mon Apr 29, 2013 8:07 pm

Yes, you're right. In the next update we will allow to choose which metric to use - memory active or memory consumed. As to the report you're looking at, then MS SQL servers as well MySQL servers are known to consume almost all chunks memory you allocate to these VMs, so seeing high value for memory consumed is expected. On the other hand, memory active shows how this memory was actively used and based on the report it doesn't seem that this VM was very busy for the reported time interval.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby cffit » Fri May 03, 2013 9:53 pm

I came on here with the same exact feeling as everyone else. I do know for a fact that reducing our SQL servers to what VEEAM suggests will render them unusable, but maybe servers not running databases or Exchange would be ok.

I also wondered about the CPU suggestions. It suggests I lower all my VMs to use 1 single CPU. I would think the CPU debate would be much less than the memory debate given CPU isn't handled like memory in the case of SQL and Exchange. Has anyone experimented with lowering their 2 and 4 CPU machines to 1 CPU based on the suggestions from this report?
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Re: Oversized VM's Report Too Agressive

Veeam Logoby Vitaliy S. » Mon May 06, 2013 9:49 am

Hi Christensen,

What is the average CPU usage for your VMs that have this recommendation of lowering the number of vCPUs? Do you have all 4 vCPUs used (you can check that via vSphere Client)?

Thanks!
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Re: Oversized VM's Report Too Agressive

Veeam Logoby cffit » Mon May 06, 2013 2:46 pm

We have about 18 VMs that have either 2 or 4 CPUs (virtual sockets) assigned, and VEEAM suggests that we change them all to 1 vCPU. Some are SQL servers, some are terminal servers using RDS, and some are application servers. I'm confused how the calculations are done, becuase if these suggestions are based on averages, and averages are based on CPU use divided by 24 hours in a day, but 16 of those hours the servers have little or no usage, doesn't that skew the "average"? I need the average to be considered the average during the 8-10 hour work day when it's in use. Taking the average over a full 24 hour day can really knock down the usage numbers.

Does Windows 2008 R2 handle removing CPUs well? I'd certainly be willing to try this out and see how it goes.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby Vitaliy S. » Mon May 06, 2013 3:51 pm

Yes, it does sound reasonable to specify business hours for these calculations, however we do search for peak usage (based on the average usage) and then compare that to current configuration to calculate the difference.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby fredbloggs » Fri Nov 29, 2013 12:26 am

Has to be stated, active memory is a very dangerous counter to report on when sizing VMs

http://blogs.vmware.com/vsphere/2013/10 ... emory.html

The issue is, whilst Veeam checks what the peak active memory counter reported you need to be a little more aware on how the application works, here's an excerpt from the above blog

This counter provides you an estimated total of amount of memory that has been touched over the sampling period. This means that depending on where you are looking at this is counter, its sampling period may be different. In vCenter for example, real-time charts show Active memory samples every 20 seconds. This means that it’s showing the estimated amount of memory that is touched by the virtual machine in the last 20 seconds. However in esxtop, the display refresh is every 5 seconds. This means that it’s showing the estimated amount of memory that is touched by the virtual machine in the last 5 seconds.

BUT – Here’s the important part - There is no way to know if the memory pages that were touched in the last number of sampling period are unique or not.


Basically, active memory may never exceed 1GB (in vcentre) but over a period of 2 minutes it could use up to 6GB of unique RAM pages and therefore you could quite easily starve your VM of much needed memory.

I'm not sure why VMware make this the default counter, nor why they've allowed the active myth to be so pervasive or the best way to report on oversized VMs, perhaps you simply shouldn't or at least include quite a big disclaimer.
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Re: Oversized VM's Report Too Agressive

Veeam Logoby Vitaliy S. » Fri Nov 29, 2013 8:32 am

Hello Fred,

Yes, I agree with you and that is why we have also included memory consumed counter into our calculations.

Thank you!
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