Running OpenFiler inside XenServer to provide Storage to other Xen instances

If you are looking to build some low cost, reliable storage for your XenServer cluster, take a look at NexentaStor. You can install this storage OS on any x86 hardware, which will keep your costs low.

With respect to how many VM's you can run from a single NAS, there is no magic answer to this question. It will depend upon a number of factors, including the NAS configuration and your client workload profile, both of which can vary significantly from deployment to deployement.

The best way to determine the best configuration is via workload profiling determined via performance testing, upon which you can make reasonable sizing and capacity planning estimates.

There is no free lunch at the end of the day..

Your going to have to add this flag to the pxe boot config "device_mapper_multipath=yes" for example:

default xenserver
label xenserver
       kernel mboot.c32
       append /tftpboot/xenserver/xen.gz dom0_mem=752M com1=115200,8n1 \
       console=com1,vga --- /tftpboot/xenserver/vmlinuz \
       xencons=hvc console=hvc0 console=tty0 \ 
       device_mapper_multipath=yes \
       --- /tftpboot/xenserver/install.img

KDB Article here :

http://docs.vmd.citrix.com/XenServer/5.6.0fp1/1.0/en_gb/installation.html#boot_from_san