The file has the format as described by man 5 fstab *except*:
- the fifth and sixth fields (fs_freq and fs_passno) are ignored. If you need fsck to run on a device before mounting it, you have to do so by a separate means, e.g. by running it from scripts/initialize (*not* prepre-start as fstab entries are already mounted at the time prepre-start is being run). But be sure that either fsck's input/outputs are tied to some tty (by setting /etc/vservers/guest/apps/init/tty or /etc/vservers/.defaults/apps/init/tty), or you supply one of the -y or -n options (man e2fsck) so that it can run non-interactively. But a better idea might be to run fsck from a startup script during the *host* boot process.
There has been some discussion between Bertl, daniel_hozac and pflanze on #vserver on 2007/02/10 about adding support for the "fs_passno" ("fsck") field, but the benefit is not entirely clear.
Jon Bendtsen wanted fsck of the filesystem and has made patches to util-vserver after daniel_hozac said where in util-vserver to make the hook. The patches uses normal fsck and normal fstab behavior. The patches can be seen and downloaded at https://savannah.nongnu.org/patch/?6213
- util-vserver:Logging on how stdin/out/err are being setup when booting vservers