Snapshot on different sized partitions show different file types

[Ronald Klop]

On Wed, 16 Feb 2011 10:33:23 +0100, Gareth Hopkins <gabbawp at gmail.com>  
wrote:

> Hi,
>
> I'm creating snapshots on a couple of partitions ranging from 10GB to  
> 31GB
>
> running file on the snapshots show different filetypes for the snapshots  
> on
> the larger than 10GB partitions.
>
> [root@ ~]# df -h /
> Filesystem     Size    Used   Avail Capacity  Mounted on
> /dev/da0s1a    9.7G    322M    8.6G     4%    /
> [root@ ~]# file /.snap/daily.0
> /.snap/daily.0: Unix Fast File system [v2] (little-endian) last mounted  
> on
> /, last written at Wed Feb 16 00:34:01 2011, clean flag 1, readonly flag  
> 1,
> number of blocks 5242880, number of data blocks 5077079, number of  
> cylinder
> groups 56, block size 16384, fragment size 2048, average file size 16384,
> average number of files in dir 64, pending blocks to free 0, pending  
> inodes
> to free 0, system-wide uuid 0, minimum percentage of free blocks 8, TIME
> optimization
>
> [root@ ~]# df -h /usr
> Filesystem     Size    Used   Avail Capacity  Mounted on
> /dev/da0s1d     31G    2.7G     26G     9%    /usr
> [root@ ~]# file /usr/.snap/daily.0
> /usr/.snap/daily.0: DOS executable (device driver)
>
> [root@ ~]# df -h /usr/local
> Filesystem     Size    Used   Avail Capacity  Mounted on
> /dev/da0s1e     15G    134M     14G     1%    /usr/local
> [root@ ~]# file /usr/local/.snap/daily.0
> /usr/local/.snap/daily.0: DOS executable (device driver)
>
> Is there some sort of limit on the snapshot size being reported to the  
> file
> system ?
>
> Cheers,
>
> Gareth

Hi, I am not authoritative in the ffs-snapshot stuff, but why would a  
snapshot always start with the same data? Maybe it is just sort of random.  
The 'file' utility just guesses the type by looking at the first N bytes  
of the file. I don't know if it has special knowledge about snapshot files.

Ronald.