ZFS snapshot name length limit? (File name too long)

[Michiel Detailleur]

Hi,

I'm using sysutils/zfs-snapshot-mgmt for automatic creation and purging 
of ZFS snapshots. It creates snapshot names like this (zfsfilesys is not 
the actual name of the zfs filesystem, it's actually a bit longer. Why 
is this important? See below.):

zfsfilesys at auto-2010-03-10_06.00

Clean and simple naming scheme you would think, but when I ls -la 
zfsfilesys/.zfs/snapshot, I get output from ls:

ls: auto-2010-03-10_06.00: File name too long

This happens for all snapshots with names longer than 16 characters for 
this particular zfs file system.

Snapshots shorter than 16 characters are listed.

drwxr-xr-x   12 root  wheel   23 Dec 24 14:06 2010-02-02-00/

The name of the actual file system is 56 characters, starting from 'tank/'
For file systems with shorters names, longer snapshot names *are* 
accessible.

This seems to imply a maximum length of 72 characters (snapshot '@' sign 
excluded) for *usable* snapshots? (usable in the sense that we can 
mount/look into them)

What limit am I (we?) hitting here? Is this a problem with ZFS itself or 
with FreeBSD? Sure looks like a silly limit for the filesystem that 
touts 'biggest everything'.

I'm using FreeBSD 8.0, the zpool was freshly created on the 8.0 OS (not 
upgraded from older FreeBSD ZFS version).

Thanks for any insight on this problem.

-- 
Michiel Detailleur
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