I am currently evaluating the use of Xen to provide instructional VMs to a large audience. I am trying to get a fairly large number of DomUs to run on one server (my goal is 100 VMs). When I get to my 58th xm create, the system crashes and restarts. There is really nothing in the /var/log/messages file or the /var/log/xen/xend.log file that identifies what went wrong. Each DomU is based off a common 4 GB basic Centos 5.1 read-only image, has a 128M swap, and a 1 GB COW file. The common image and swap are Logical Volumes. The COW file is a sparse file mounted with unionfs in the DomU. The DomU''s are all configure to start with 128M of RAM. I have a Dual Intel Quad Core (E5420) server with 16GB of ram and a Seagate Sata 1TB hard drive. I am running kernel 2.6.18-53.1.14 from the Centos 5.1 distribution, with all package updates applied. Does anybody have any ideas about what could be going wrong here, or how to investigate this in more detail. Are there some System hard limits I am running up against (e.g., number of mounted file systems or number of network devices)? I saw a thread discussing an old fixed limit of 256 for Blktap devices, but when I look at /dev/xen, I am far below this limit. (The COW is the only tap:io device for each DomU). Thanks, SteveH _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users