how many partitions on a slice?

Viktor Lazlo viktorlazlo at
Fri Jun 20 02:37:55 PDT 2003

On Fri, 20 Jun 2003, sweetleaf wrote:

> I choose to use the entire disk during freebsd install. Ok, that creates
> 1 really large slice correct? Now within this slice how may partitions
> cam there be? I tried setting up /root /tmp /home /var /usr /sandbox/
> /private /storage ..... after adding sandbox and attempting to add
> /private and /storage i saw that the partitions looked different in the
> freebsd disk setup tool. I continued anyway but upon the system setting
> up the previous entries and formatting them i received messages that
> /private and /storate were not mountable or something like that...anyway
> i had to start over and only add six partitions..well other that the
> swap. Should i setup 2 slices? here is my current setup with the six
> partitions.
>  df -h
> Filesystem    Size   Used  Avail Capacity  Mounted on
> /dev/ad0s1a   290M   274M  -7.3M   103%    /
> devfs         1.0K   1.0K     0B   100%    /dev
> /dev/ad0s1f   965M   2.0K   888M     0%    /home
> /dev/ad0s1g   965M   2.0K   888M     0%    /private
> /dev/ad0s1e   484M    12K   445M     0%    /tmp
> /dev/ad0s1h    33G   1.7G    29G     6%    /usr
> /dev/ad0s1d   145M   9.7M   124M     7%    /var

I'm not sure if any changes have been introduced since 5.x but
'traditional" FreeBSD has a maximum of 4 slices (BIOS or DOS partitions)
per disk, each of which can contain up to 8 partitions (the BSD
filesystems, labelled a-h).

Most commonly on a single hard drive system, you would either devote the
whole disk to a single FreeBSD slice or have 1 DOS/Windows slice and 1
FreeBSD slice if you are dual-booting.  You would only need additional
FreeBSD slices if you need more partitions than a single slice allows.

Within the main FreeBSD slice, partitions a and b are reserved for /root
and swap respectively, and c refers to the partition as a whole;  By
convention, partition d was formerly reserved and while there's probably
no problem now in using it as an ordinary partition it is not usually
recommended for general use, leaving the available partitions e, f, g and

How you divide up the remaining partitions depends mainly on what you are
using the machine for and how much space any of those functions require.
In general any sets of files you want contained for easy administration or
to prevent conflicts with other files systems are best set up in their own
partitions.  You will definitely want /usr in its own partitions, and /var
as well to prevent mail and logs spawned by a process running amok or as a
result of a DOS attempt from filling up your other filesystems.  /home is
a good candidate for it's own partition as well to allow easy containment
of users data for backups or moving to a different machine. If you are
using the server for an ftp or file server, those data files are best
stored on a dedicated partition as well.

I'm not sure I'd bother giving /tmp it's own partition--applications that
rely heavily on tmp space tend to use /usr/tmp or /var/tmp more often than
/tmp anyways (at least in my experience), so I just make sure /var is
large enough to hold it's own contents as well as any temporary files
created by any applications. Depending on what you are using /private,
/storage and /sandbox for you may want to set up a secondary slice to
allow them to have their own partitions or set them up as separate
filesystems within an existing partition.



More information about the freebsd-questions mailing list