Cache Limit in V6

mcamino · Thu Nov 08, 2012 12:32 pm

Hello,
I am attempting to setup some ISCSI devices and after 3 devices i can no longer add any additional devices with cache, either write back or read through modes. they are greyed out automatically. Can you help me troubleshoot this?

Thu Nov 08, 2012 1:18 pm

You're most probably running out of a free physical memory. With upcoming version you'd be able to change existing devices cache size dynamically, for now allocation is static (like with hard disks and RAID controllers).

mcamino · Thu Nov 08, 2012 2:36 pm

I have 12gb ramm and i have 8gb free at this time. Starwind process is only using about 1.9gb of memory

Thu Nov 08, 2012 4:14 pm

Can you capture Task Manager screenshots with RAM usage when you add targets one-by-one? So...

1) Nothing added
2) 1st added
3) 2nd added
3) 3d added
4) Attempt to add 4th, error reported

?

Thanks!

mcamino wrote:I have 12gb ramm and i have 8gb free at this time. Starwind process is only using about 1.9gb of memory

mcamino · Sat Nov 10, 2012 11:57 am

I figured out my problem. Apparently even though i have PAE enabled on 2008 x32, there is also a 2gb limit on memory per process. I was able to raise it to 3gb for the starwind process and my problem was temporarily resolved.

http://support.microsoft.com/kb/316739

I would like to make a suggestion for your next version of your software. Besides allowing us to setup cache sizes dynamically, can we get an option to have each cache/lun run as a separate process in windows? If each lun has a separate threaded process, then each cache/lun will be limited to 2gb-3gb and that will be great because i can run 4 x 2gb process and still have 4gb free for system memory needs.

Sat Nov 10, 2012 12:01 pm

Thank you for keeping us in loop.

Unfortunately that's not so easy... We also require some PTEs from kernel which is limited to 2GB of a virtual address space (and 1GB in your case with /3GB option) when running on 32-bit. So we'll spend quite a time doing half-baked and half-ass solution. I'd recommend to think about switching to 64-bit OS / architecture as it's not suffering from 2^32 limitation in any case.

mcamino wrote:I figured out my problem. Apparently even though i have PAE enabled on 2008 x32, there is also a 2gb limit on memory per process. I was able to raise it to 3gb for the starwind process and my problem was temporarily resolved.

http://support.microsoft.com/kb/316739

I would like to make a suggestion for your next version of your software. Besides allowing us to setup cache sizes dynamically, can we get an option to have each cache/lun run as a separate process in windows? If each lun has a separate threaded process, then each cache/lun will be limited to 2gb-3gb and that will be great because i can run 4 x 2gb process and still have 4gb free for system memory needs.