/usr/home vs /home

[Matthew Seaman]

On 18/02/2012 10:44, Da Rock wrote:
> I have yet to try ZFS (lack of resources really), but when I can I will
> setup a SAN and it will be interesting to see how this works and I
> probably will use a single partition. But for the general filesystem I
> doubt a single partition will cut it (I could be a stick in the mud
> though :) ), and I highly recommend this path for the new user;
> especially using a desktop.

Your statement here makes some assumptions about the way ZFS works which
aren't the case.

ZFS doesn't have partitions in the sense of areas of disk space reserved
for a particular filesystem.

It has two concepts: the zpool and the zfs.

The zpool is about the collection of hardware used to provide the disk
space.  This incorporates all of the ideas about mirroring or RAIDZx or
log devices of various types or spare drives.  (Essentially what you'ld
otherwise get from a very expensive raid controller.)

The zfs is a chunk of filesystem namespace designated for a specific
purpose.  You can use a zfs as a raw partition, but it is very much more
common for it to be used as a filesystem.

zfses look quite a lot like partitions, but they are really quite
fundamentally different.  The basic storage unit used by ZFS is a 128kB
block.  The blocks used by a particular zfs can appear anywhere on the
zpool, and unless the ZFS has been administratively limited to a
particular size, the free space available to the zfs is exactly the free
space available on the entire zpool.

Looked at that way, you can see it as essentially one big partition
spanning the entire zpool.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW

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