topic Re: Adding extra memory to vsa in StoreVirtual Storage

Adding extra memory to vsa

M.Braak — Thu, 01 Dec 2011 17:41:45 GMT

Does anyone know if extra added memory to a vsa will be used for caching or will it not be used?

Re: Adding extra memory to vsa

oikjn — Fri, 02 Dec 2011 01:31:51 GMT

I did. It definitely doesn't use all available memory. I think I heard somewhere on the forum that it uses a fixed size in proportion to the total HDD size.

Re: Adding extra memory to vsa

Bart_Heungens — Fri, 02 Dec 2011 21:34:50 GMT

Hi,

The size of RAM depends of the amount of disks behind the VSA...

Recommendations are:

1GB RAM up to 4,5 TB of disks

2GB RAM from 4,5 up to 9 TB

3GB RAM from 9 to the max supported 10 TB...

More details in theP4000 VSA Installation and Configuration Guide

http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c01727958/c01727958.pdf

Kr,

Bart

Re: Adding extra memory to vsa

M.Braak — Fri, 02 Dec 2011 22:38:37 GMT

Bart,

I know those numbers but for as i know saniq needs that amount of memory to function properly. My question is: does saniq use extra memory assigned for caching of blocks or not? (Does it increase the cache hit rate?)

Re: Adding extra memory to vsa

Bart_Heungens — Sat, 03 Dec 2011 06:09:25 GMT

Hi,

Not as far as I know... Never tested it yet...

I assume it is not since the VSA uses the virtual storage controller provided by VMware or Hyper-V and that's it...

Kr,

Bart

Re: Adding extra memory to vsa

oikjn — Sun, 04 Dec 2011 14:44:39 GMT

it definitely does not.

because I setup a VSA only host, I had a bunch of spare memory and just assigned it to the VSAs because I figured I would try. they run at a constant memory allocation and for an 850GB VSA, that runs 3.55GB memory w/ 2.77GB+ free. I also have a 1.3TB VSA with 2.88GB memory that has 1.96GB free memory.

I assume if you put in a 10TB VSA it will use more memory, but it definitely does not CACHE with the free memory... I'm using Hyper-V so I figure the best way to get that is simply keep the memory free on the host... not ideal, but better than nothing.

Re: Adding extra memory to vsa

M.Braak — Sat, 10 Dec 2011 19:32:22 GMT

Ok so adding memory is not effective. I also want to know who is having problems with cpu usage of the vsa. I have a lot of 100% cpu usage on different vsa clusters. Adding a vcpu is not supported and the vsa also doesnt do mulithreading very well. So seems the vsa is only usable in very low workloads.