zfs discuss - Dec 2009 - Heads-Up: Changes to the zpool(1m) command

Some new features have recently integrated into ZFS which have change
the output of zpool(1m) command. Here''s a quick recap:

1) 6574286 removing a slog doesn''t work

This change added the concept of named top-level devices for the purpose
of device removal. The named top-levels are constructed by using the
logical name (mirror, raidz2, etc) and appending a unique numeric
number. After this change ''zpool status'' and ''zpool
import'' will now
print the configuration using this new naming convention:

jaggs# zpool status tank
   pool: tank
  state: ONLINE
  scrub: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         tank        ONLINE       0     0     0
           raidz2-0  ONLINE       0     0     0
             c0t0d0  ONLINE       0     0     0
             c1t0d0  ONLINE       0     0     0
             c4t0d0  ONLINE       0     0     0
             c6t0d0  ONLINE       0     0     0
             c7t0d0  ONLINE       0     0     0

errors: No known data errors

2) 6677093 zfs should have dedup capability

This project modified the default ''zpool list'' to show the
"dedupratio"
for each pool. Subsequently a new property, "dedupratio", is available
when using ''zpool get'':

jaggs# zpool list
NAME     SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
export   928G  47.5G   881G     5%  1.77x  ONLINE  -
rpool    928G  25.7G   902G     2%  1.40x  ONLINE  -

jaggs# zpool get dedup rpool
NAME   PROPERTY    VALUE  SOURCE
rpool  dedupratio  1.40x  -

3) 6897693 deduplication can only go so far

The integration of dedup changed the way we report report "used" and
"available" space in a pool. In particular, ''zpool
list'' reports
"allocated" and "free" physical blocks opposed to
''zfs list'' shows
"used" and "available" space to the filesystem. This change
replaced the
the "used" property with "allocated" and
"available" with "free". This
should help clarify the accounting difference reported by the two
utilities. This does, however, impact any scripts which utilized the old
"used" and "available" properties of the zpool command.
Those scripts
should be updated to use the new naming convention:

jaggs# zpool list
NAME           SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
rpool          464G  64.6G   399G    13%  1.00x  ONLINE  -
tank          2.27T   207K  2.27T     0%  1.00x  ONLINE  -

jaggs# zpool get allocated,free rpool
NAME   PROPERTY   VALUE  SOURCE
rpool  allocated  64.6G  -
rpool  free       399G   -


We realize that these changes may impact some user scripts and we 
apologize for any inconvenience this may cause.

Thanks,
George