# mount: /dev/da0p3: Invalid argument



## balanga (Jul 14, 2018)

I get mount: /dev/da0p3: Invalid argument when trying to mount p3 on a GPT disk which is shown by gpart as a 5G freebsd-ufs partition.

I thought I had installed FreeBSD on this disk but can't mount it to check

file -s /dev/da0p3 shows data.

Is there any direct way to see what is on this partition?

Would `dd if=/dev/da0p3 of=part3 bs=1m count=1000` show me what is on the disk?

Presumably, I would be able to recognise if this was a FreeBSD installation, and if not should a `newfs /dev/da0p3` allow me to mount it


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## balanga (Jul 14, 2018)

In answer to my own post (in case I'm in the same position again..) yes I can mount it and a file called .snap gets created


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## Beastie (Jul 14, 2018)

FWIW, the .snap is a directory and it only _appeared_ when you mounted the partition. It was _created_ by newfs(8) along with the file system and it's used for generating snapshots of the file system.

newfs(8):

```
-n         Do not create a .snap directory on the new file system. The
         resulting file system will not support snapshot generation
```

dump(8):

```
-L         This option is to notify dump that it is dumping a live file sys-
         tem. To obtain a consistent dump image, dump takes a snapshot of
         the file system in the .snap directory in the root of the file
         system being dumped and then does a dump of the snapshot. The
         snapshot is unlinked as soon as the dump starts, and is thus
         removed when the dump is complete. This option is ignored for
         unmounted or read-only file systems. If the .snap directory does
         not exist in the root of the file system being dumped, a warning
         will be issued and the dump will revert to the standard behavior.
         This problem can be corrected by creating a .snap directory in
         the root of the file system to be dumped; its owner should be
         ``root'', its group should be ``operator'', and its mode should
         be ``0770''.
```


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