Re: Multiple priviliged domains

["Jan Kundrát" <jan.kundrat@fzu.cz>]

Ian Pratt wrote:
>>3. I don't seem to be able to create more than 8 VBDs. [I am using 
>>xen-2.0.1-src.tgz.]  While trying to start 5 domains, each of which had 
>>two "scsi" disks (/ and swap), I discovered that the 5th domain wouldn't 
>>start until I removed the swap disks from both the 4th and 5th domains' 
>>configuration files -- i.e., not exceeding 8 VBDs total.  A cursory search 
>>through the code didn't reveal any relevant #define's, and I didn't see 
>>anything about this in the Xen docs, so before I look further I thought 
>>I'd ask the list if this is a known limit.  (If so, I am surprised the VBD 
>>structures aren't allocated dynamically to prevent this?)  A search of the 
>>mailing list revealed a message from Ian on 2004-03-10 stating "Mark wrote 
>>a pretty good readme on VBDs and put it in the tree", but I couldn't find 
>>the readme; is it still part of the tree?
> 
> 
> Are you using loop files? If so, Linux has a statically compiled
> allocation, set to 8 by default. Fixing this and submitting the
> patch to lkml would a good thing...
> 
> I don't believe the VBD code has any such limitations. (We tend
> to use LVM rather than loop files).

If you use files as backend for VBDs in domain0, you use loop device. If 
the CONFIG_BLK_DEV_LOOP in dom0 kernel is compiled as module, you can 
use max_loop parameter while doing modprobe/insmod. And if it's compiled 
directly into the kernel, use max_loop=n boot option.

jkt


-- 
cd /local/pub && more beer > /dev/mouth



-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/