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Cache Limit in V6

Posted: Thu Nov 08, 2012 12:32 pm
by mcamino
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?

Re: Cache Limit in V6

Posted: Thu Nov 08, 2012 1:18 pm
by anton (staff)
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).

Re: Cache Limit in V6

Posted: Thu Nov 08, 2012 2:36 pm
by mcamino
I have 12gb ramm and i have 8gb free at this time. Starwind process is only using about 1.9gb of memory

Re: Cache Limit in V6

Posted: Thu Nov 08, 2012 4:14 pm
by anton (staff)
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

Re: Cache Limit in V6

Posted: Sat Nov 10, 2012 11:57 am
by mcamino
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.

Re: Cache Limit in V6

Posted: Sat Nov 10, 2012 12:01 pm
by anton (staff)
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.