vServer experience (Brent Chun)
New set of scaling issues: disk footprint
- 1581 directories, 28959 files
VM-specific copy-on-write reduced 29 MB/vm
- copied part: 5.6 MB /etc, 18.6 MB /var
- 1000 VMs per disk
Current
- 222+ per node
- 30-40 secs create, 10 secs delete
- developing VM preallocate & cache
slice login -> vserver root
Limitations
- common OS for all VMs (few calls for multiple OS’s)
- user-level NFS mount (MIT’s on it)
- incomplete self-virtualization
- incomplete resource isolation (eg. buffer cache)
- inperfect (but unbroken) kernel security
=> raised the bar on isolation kernels