The /vz directory is on the same partition than my system (it's an integration server).
My partition is /dev/sda1 and I can run glusterFSd on my HN.
tune2fs 1.40-WIP (14-Nov-2006)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: ddc5c511-e274-4c72-a9d5-5c34b7255e92
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
[B]Filesystem features: has_journal ext_attr resize_inode dir_index filetype[/B]
needs_recovery sparse_super large_file
Filesystem flags: signed directory hash
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 18792448
Block count: 37570002
Reserved block count: 1878500
Free blocks: 36303058
Free inodes: 18711149
First block: 0
Block size: 4096
Fragment size: 4096
Reserved GDT blocks: 1015
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 16384
Inode blocks per group: 512
Filesystem created: Mon Feb 9 11:37:38 2009
Last mount time: Mon Feb 9 20:11:30 2009
Last write time: Mon Feb 9 20:11:30 2009
Mount count: 5
Maximum mount count: 30
Last checked: Mon Feb 9 11:37:38 2009
Check interval: 15552000 (6 months)
Next check after: Sat Aug 8 12:37:38 2009
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 128
Journal inode: 8
First orphan inode: 11733633
Default directory hash: tea
Directory Hash Seed: 245cffd2-af21-4e9d-928b-a969580c16a1
Journal backup: inode blocks