topic Re: HPVM dynamic memory question in Operating System - HP-UX

HPVM dynamic memory question

likid0 — Fri, 05 Dec 2008 07:32:30 GMT

Hy, let's see if I can explain my self with this rusty english of mine.

let's say I have 20G of memory on the host for the VMs.

So I create 4 vm with 5 gigs of ram(-r 5G ),then I configure dynamic memory on the 4vm.

So what I need(some times) is to be able to dynamically reduce the memory on vm1 to 2G ( -x target_memory 2G) and give the 3G to vm2 so vm2 ends up with the 8G it needs at that moment.

But if you try on VM2 to do the -x target_memory 8G it says your max mem is 5g change with -r , an to do this you need a reboot.

if I reboot and give it -r 7g it's not going to be able to boot anyway.

So what can you do to implement this Idea with dynamic memory, reducing memory is not the problem, but what's the point if you can't extend it on other VM's ?

arf, i'm not sure it's clear but I tried ...

Thnx

Re: HPVM dynamic memory question

Jozef_Novak — Fri, 05 Dec 2008 10:10:26 GMT

Hello,

first of all, if you have a server with 20GB of memory, you cannot create 4 guests with 5GB of memory each. Certain amount of system memory has to be allocated for the VM host system that runs the HPVM software.

For detailed memory requirements of HPVM, see the lates HPVM guide at:

http://docs.hp.com/en/vse.html#HP%20Integrity%20Virtual%20Machines

Check the guide relevant for your version of HPVM.

J.

Re: HPVM dynamic memory question

likid0 — Fri, 05 Dec 2008 10:19:19 GMT

as i said:

let's say I have 20G of memory on the host for the VMs.

I allready have memory reserved for the host. And then I am left with 20 gigs only for the vm

And I have been to the doc a couple of times and my question isn't address there.

thnx

Re: HPVM dynamic memory question

Jozef_Novak — Fri, 05 Dec 2008 10:30:51 GMT

Okay, sorry, I did not realise that those 20GB were exclusive for VMs from your initial post.

From the error messages that you describe, it looks that -x ram_dyn_max parameter is too low.

Have you set the following parameters during the VM creation ?

-x ram_dyn_type = any | driver
-x ram_dyn_min = minimum size for memory size changes
-x ram_dyn_max = maximum size for memory size changes

if yes, what is the ram_dyn_max value for the vm2 ?

J.

Re: HPVM dynamic memory question

likid0 — Tue, 09 Dec 2008 08:22:48 GMT

This is the config:

[Dynamic Memory Information]
Type : driver
Minimum memory : 512 MB
Target memory : 4154 MB
Maximum memory : 5114 MB
Current memory : 4154 MB
Comfortable minimum : 3002 MB
Boot memory : 5114 MB
Free memory : 953 MB
Available memory : 444 MB
Memory pressure : 0
Memory chunksize : 65536 KB
Driver Mode(s) : STARTED ENABLED

But if you try to increase ram_dyn_max beyond the Total memory if gives you and error:

hpvmmodify: WARNING (vmfcont): Value 6144 MB for ram_dyn_max must be less than or equal to ram_size value 5120 MB.

Re: HPVM dynamic memory question

Eric SAUBIGNAC — Wed, 10 Dec 2008 08:56:20 GMT

Bonjour Orange_adm,

Not yet played with dynamic memory. No need for the moment.

Anyway, found this on page 143 from T2767-90141 "HP Integrity Virtual Machines Version 4.0 Installation, Configuration, and Administration", chapter 9.6.3.1 "Dynamic Memory Restrictions" :

-------------------------------------------
The size of a virtual machine cannot be increased above its original boot size (as specified with the -r option).
-------------------------------------------

In other words I understand that you must configure each VM with the -r option with the maximum memory you plan to allocate to the VM.

Not sure, and I will do some tests later, but I also guess that if you plan that each VM can sometimes grows to 8 Go, you will need more than 20 Go free memory on the host at startup of the VMs.

Eric

Re: HPVM dynamic memory question

likid0 — Thu, 11 Dec 2008 07:42:16 GMT

Not sure, and I will do some tests later, but I also guess that if you plan that each VM can sometimes grows to 8 Go, you will need more than 20 Go free memory on the host at startup of the VMs.

Yes, that's my point Eric, looks like you can't give more memory to the host, than the one you have at free at startup.

I think you should be able to increase this, you should be able to give it a min_mem, boot_mem and max_mem. the boot_mem the memory needed to boot and max_mem a maximun well over the actuall memory just in case you need increase it dynamicly, similiar as aix does on it's pseries.

Hope it comes some time in the future

Re: HPVM dynamic memory question

OScar123 — Wed, 04 Apr 2012 10:33:45 GMT

Even I have the same doubt. Has this been taken care in current release 4.3 .

Just want to know how to manage dynamic memory.

Is it mandatory to set startup memory using -r option . Because as an example if I set memory of two VM's as per below command

hpvmmodify -P host1 -r 6G \
-x ram_dyn_type=any \
-x ram_dyn_min=1222M \
-x ram_dyn_max=10G \
-x ram_dyn_target_start=2G

I wont be able to increase memory in both the VM beyond 6 GB due to -r option. And even if i want to reduce the memory on VM1 by 2 Gb and assign it to VM2 to make it 8GB I wont be able to since again -r 6G was used earlier it will not allow to do so

So please tell me What if I dont mention -r option and only specify the following paramters with hpvmmodify .

hpvmmodify -P batman -x ram_dyn_min=1222M

hpvmmodify -P batman -x ram_dyn_max=10G

hpvmmodify -P batman -x ram_dyn_target_start=4G

This is not mention in HP doc . Will it work. WIll the VM boot with 4G and later when i want i can increase it till 10G.