Partition naming conventions

[Matthew Dillon]

:Out of morbid curiosity...
:
:Is there any danger in deviating from the normal partition naming 
:convention (a=/, b=swap, c=overlay)?  For that matter, what tools still 
:require the overlay partition, if any?

    Since we are 4.x based partition c is still 'magic', so you
    can't use it as a general partition.  However, the partition limit
    in DragonFly (as of recently) is 16 rather then 8 so you have lots of
    partitions to play with.

    The kernel tries to mount 'a' as the root partition by default, and
    there are BIOS limitations to contend with as well, so it's a good 
    idea to put root on 'a'.  Partition 'b' does not have to be swap but
    it is usually assigned to swap by convention.  Everything else is
    up for grabs.

    My recommendations are outlined in the LiveCD's README:

        #
        #       ad0s1a  256m            This will be your /
        #       ad0s1b  1024m           This will be your swap
        #       ad0s1c                  (leave alone)
        #       ad0s1d  256m            This will be your /var
        #       ad0s1e  256m            This will be your /tmp
        #       ad0s1f  8192m           This will be your /usr (min 4096m)
        #       ad0s1g  *               All remaining space to your /home


    If you have a large system, it is often a good idea to separate
    out oft-written directories such as /usr/obj, and to make /tmp
    larger.  /var/tmp is usually made a softlink to /tmp.  If you have
    or intend to process a lot of mail, making /var larger is a good
    idea.  If you are running a mail server it is often a good idea
    to make /var/spool its own partition (and /var/mail its own 
    partition if you are running a large mail pop service or have a lot
    of users).  If you are running a large web server making
    /usr/local/www its own partition (the base of Apache's site directory)
    is a good idea.

    As a point of reference, here is how I have the main DragonFly machine
    setup:

crater:/usr/local/www> df
Filesystem            1K-blocks     Used    Avail Capacity  Mounted on
/dev/da0s1a              128990    95894    22778    81%    /
/dev/da0s2e            13419070   119686 12225860     1%    /news
/dev/da0s2f            13419070   501394 11844152     4%    /rdbms
/dev/da0s2h            13419070  1234660 11110886    10%    /ftp
/dev/da0s1f              257998    46604   190756    20%    /tmp
/dev/da0s1h            12783794  3214364  8546728    27%    /usr
/dev/da0s2g            13419070     2700 12342846     0%    /usr/local/www/site
/dev/da0s1e              257998    83320   154040    35%    /var
/dev/da0s1g             1032142     1896   947676     0%    /var/spool
/dev/da1s1e             4129310  1493872  2305094    39%    /usr/src
/dev/da1s1f            66437000   443838 60678202     1%    /cvs
procfs                        4        4        0   100%    /proc

    e.g. the machine does a lot of mail routing but does not have many
    actual accounts, hence /var/spool is broken out.  The machine runs
    a significant web server hence /usr/local/www/site.  The machine
    runs a news server hence /news, and an ftp server hence /ftp.  I
    made the root too small (128MB isn't quite sufficient for comfort).

    I backup all of these partitions independantly... in fact, my backup
    policities pretty much governed how I set the partitions up.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>