a literal colon in a zpool name is allowed, which contradicts the man page

[dajhorn]

The man page says this about zpool create:

Creates  a  new  storage  pool containing the virtual devices specified on the command
line. The pool name must begin with a letter, and can only contain alphanumeric  char‐
acters as well as underscore ("_"), dash ("-"), and period ("."). The pool names "mir‐
ror", "raidz", "spare" and "log" are reserved, as are names beginning with the pattern
"c[0-9]". The vdev specification is described in the "Virtual Devices" section.

However, a zpool can have a literal colon in its name like this:

# zpool create zfs:foobar /dev/sdb
# zpool list zfs:foobar
NAME         SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
zfs:foobar  9.94G   108K  9.94G     0%  1.00x  ONLINE  -
# zpool status zfs:foobar
  pool: zfs:foobar
 state: ONLINE
 scan: none requested
config:

        NAME        STATE    READ WRITE CKSUM
        zfs:foobar  ONLINE      0     0     0
          sdb       ONLINE      0     0     0

Is the man page incorrect?

This is somewhat problematic because the dracut scripts assume that zfs: is a safe prefix to use for overloading the root= kernel parameter.

[behlendorf]

Yes, the man page is incorrect and should be fixed. See zpool_name_valid()->pool_namecheck()->valid_char() in the source. Allowed characters are a-z, A-Z, 0-9, -, _, ., and :. We can't really change this either since I'm sure there currently exist pool names which use the colon and removing it would break compatibility. Perhaps we can update the dracut scripts.

[dajhorn]

The secondary issue in dracut/ should be reticketed.