Ram resource tuning...

[Davek0974]

Is there a rule by which you tune ram allocation on guests?

If I install a new vim, take the default allocation and get it running, what guidance do I use to correctly tune the ram allocation later for optimal resource usage and performance of the guest??

I know there are the performance counters for ram but what do I look out for? Maximum guest usage, zero ballooning, 90% guest usage, 75% allocation usage etc??

I know I could just throw ram at them all but ram costs money and I like things properly set, in a physical machine you don't this sort of flexibility so there seems no comparison.

Any ideas?

[CHUNTAO56]

Hello Davek0974

Hope doing great

You can customize the RAM to be available for VM time of installation or after installation

Please let us know what product and version you are going to configure.

"You must BE the change you wish to see in the world."

[NuggetGTR]

There is no real "rule" the only rule is dont over allocate RAM basically. but the way ESX/i works it will take back what's not being used anyway so does mitigate some of that.

Things like is it a 32bit OS in this case there is no need to allocate over 4GB, Guess what I do is take a best guess, Say I have a new virtual running windows 2008 R2 64bit and it will be running SAP, now I know sap requires quiet a bit of memory so I would give it 6GB and then monitor its usage, I look for Active RAM which indicates how much is actively being used, I also look at Consumed and granted. If its only consuming 4GB and only has say 1.5GB active I would then wind the RAM back to 4GB.

There is no real science to it just have to use some common scence and know the products being used. remember as patches get applied more memory could be used by the OS so give it a little breathing room.

Active, consumed and granted are the ones to look for for guest imo if you want to tune the guests RAM, also OS counters have a look to see how much is being paged etc.

[StressedOut]

Hi all, i am the same guy as the OP, i tried logging in using my home account but it wont let me switch for some reason?

Any way, i have had a look at my memory configuration and the details are as follows...

XP 32bit              Configured=2.0gb, granted=2.0gb, consumed=1.6gb, active=0.6gb

XP 32bit              Configured=4.0gb, granted=3.0gb, consumed=2.5gb, active=2.0gb

2003sbs 32bit      Configured=4.0gb, granted=4.0gb, consumed=3.3gb, active=1.3gb

2008r2 RDS         Configured=16gb, granted=16gb, consumed=8.0gb, active=0.4gb

The one that is most baffling is the RDP server, it has 16 sessions running on it, and is only using 0.4gb of ram?? I know the allocation is high but i was expecting to use about 1gb per user.

Should i adjust these figures, and if so, what sort of values should i go for? Also, how did you arrive at thos values?

Many thanks

Davek0974

[Davek0974]

Anyone??

[NuggetGTR]

Think you can cut back on the RDS/P? server its only consuming 8GB than I would be cutting it back down to about that much.

TS server can cop a huge load but it all depends on what the people are doing, if its purely a jump box then it most likely wouldn't be using much.

I would think it should be using actively using more memory but hey strange things happen, it has consumed 8GB so its used that much of the 16GB but at the time of monitoring it was only actively accessing 400MB of it.

[StressedOut]

Thanks for that,

I cut it down to 12gb this morning and no effects, will keep monitoring and trimming.

Dave