RAIDZ capacity (was ZFS version 15 committed to head)

[Stefan Bethke]

Am 17.07.2010 um 12:51 schrieb Marco van Lienen:

> On Sat, Jul 17, 2010 at 12:25:56PM +0200, you (Stefan Bethke) sent the following to the -current list:
>> Am 17.07.2010 um 12:14 schrieb Marco van Lienen:
>> 
>>> # zpool list pool1
>>> NAME    SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
>>> pool1  5.44T   147K  5.44T     0%  ONLINE  -
>> ...
>>> zfs list however only shows:
>>> # zfs list pool1
>>> NAME    USED  AVAIL  REFER  MOUNTPOINT
>>> pool1  91.9K  3.56T  28.0K  /pool1
>>> 
>>> I just lost the space of an entire hdd!
>> 
>> zpool always shows the raw capacity (without redundancy), zfs the actual available capacity.
> 
> I have read many things about those differences, but why then does zfs on opensolaris report more available space whereas FreeBSD does not?
> That would imply that my friend running osol build 117 couldn't fill up his raidz pool past the 3.56T.

You didn't show us how your friends pool is set up.

With RAIDZ1, the capacity of one of the devices in the pool is used for redundancy, with RAIDZ2 it's two disks worth.  So three 2TB disks with RAIDZ1 gives you 4TB net capacity.  If you don't care about redundancy, use a simple concatenation, i. e. don't specify mirror, raidz or raidz2 when creating the pool.


Stefan

-- 
Stefan Bethke <stb at lassitu.de>   Fon +49 151 14070811