/var and /usr - Setup

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  1. /var and /usr

    Why is it said that /var should reside on a separate partition from /
    usr ?

  2. Re: /var and /usr

    Le 14.10.2008 08:31, annalissa a écrit :
    > Why is it said that /var should reside on a separate partition from /
    > usr ?


    For instance: /var is the place where logs are written, suppose some
    process becomes mad and fill the partition with logs....

    --
    François Patte
    Université Paris Descartes

  3. Re: /var and /usr

    On Tue, 14 Oct 2008 08:50:06 +0200, François Patte wrote:

    >Le 14.10.2008 08:31, annalissa a écrit :
    >> Why is it said that /var should reside on a separate partition from /
    >> usr ?

    >
    >For instance: /var is the place where logs are written, suppose some
    >process becomes mad and fill the partition with logs....


    And /usr may be mounted read-only.

    Grant.
    --
    http://bugsplatter.id.au/

  4. Re: /var and /usr

    François Patte wrote:
    > Le 14.10.2008 08:31, annalissa a écrit :
    >> Why is it said that /var should reside on a separate partition from /
    >> usr ?

    >
    > For instance: /var is the place where logs are written, suppose some
    > process becomes mad and fill the partition with logs....
    >

    Yes. /var is for /variable/ data. Logs and often databases live there.

    So it can grow and possibly exceed limits: having it separate from the
    parts that are necessary for recovery from such a state, means you CAN
    recover..

  5. Re: /var and /usr

    Grant wrote:

    > And /usr may be mounted read-only.


    And /var may be mounted noexec.

    Mark.

    --
    Mark Hobley,
    393 Quinton Road West,
    Quinton, BIRMINGHAM.
    B32 1QE.

  6. Re: /var and /usr

    annalissa wrote:
    > Why is it said that /var should reside on a separate partition from /
    > usr ?


    Because the root "/" filesystem should never be allowed to fill up.
    If it does, all kinds of nastiness can occur.

    And var is one of the partitions on which programs dump their data,
    especially e-mail and news, web proxies, log files, etc.

    It's a safeguard.
    --
    | spike1@freenet.co.uk | "I'm alive!!! I can touch! I can taste! |
    | Andrew Halliwell BSc | I can SMELL!!! KRYTEN!!! Unpack Rachel and |
    | in | get out the puncture repair kit!" |
    | Computer Science | Arnold Judas Rimmer- Red Dwarf |

  7. Re: /var and /usr

    annalissa writes:

    >Why is it said that /var should reside on a separate partition from /
    >usr ?


    Many things are said. Not all are sensible.
    Anyway, /var/ is written to. /usr is in general not. So /var can fill up.


  8. Re: /var and /usr

    =?ISO-8859-1?Q?Fran=E7ois_Patte?= writes:

    >Le 14.10.2008 08:31, annalissa a écrit :
    >> Why is it said that /var should reside on a separate partition from /
    >> usr ?


    >For instance: /var is the place where logs are written, suppose some
    >process becomes mad and fill the partition with logs....


    So what? /usr is not written to, and you can read from a full partition.
    And /var is far more likely to fill up if it is on a separate partition
    (that spare space on /usr is not available to it).



    >--
    >François Patte
    >Université Paris Descartes


  9. Re: /var and /usr

    François Patte wrote:
    > Le 14.10.2008 08:31, annalissa a écrit :
    >> Why is it said that /var should reside on a separate partition from /
    >> usr ?

    >
    > For instance: /var is the place where logs are written, suppose some
    > process becomes mad and fill the partition with logs....
    >


    And /var/spool/mail, /var/spool/news, /var/spool/mqueue and /var/tmp/. Any of
    those may be overflowed quite badly.

    The separation of /var also goes back to the days of much smaller disks, when
    a modest mail spool would be wise to put on a separate disk or partition.

  10. Re: /var and /usr

    On 2008-10-14, Unruh wrote:
    >=?ISO-8859-1?Q?Fran=E7ois_Patte?= writes:
    >
    >>For instance: /var is the place where logs are written, suppose some
    >>process becomes mad and fill the partition with logs....

    >
    > So what? /usr is not written to, and you can read from a full partition.
    > And /var is far more likely to fill up if it is on a separate partition
    > (that spare space on /usr is not available to it).


    That's just the reason to separate /var from the rest of the filesystem.
    One reason to separate /usr from the rest of the filesystem is to make
    upgrades easier; you can mke2fs the /usr partition to wipe all vestiges
    of old binaries clean and start fresh. (Grant already mentioned another
    reason, the ability to mount /usr read-only.)

    --keith


    --
    kkeller-usenet@wombat.san-francisco.ca.us
    (try just my userid to email me)
    AOLSFAQ=http://www.therockgarden.ca/aolsfaq.txt
    see X- headers for PGP signature information


  11. Re: /var and /usr

    keith writes:
    > That's just the reason to separate /var from the rest of the filesystem.


    Another reason is to eliminate write activity on the partition containing
    /usr thereby increasing reliability.
    --
    John Hasler
    john@dhh.gt.org
    Dancing Horse Hill
    Elmwood, WI USA

  12. Re: /var and /usr

    On Oct 13, 10:31 pm, annalissa wrote:
    > Why is it said that /var should reside on a separate partition from /
    > usr ?


    How about an example and some reference documentation:
    $ mount | awk '{if($3=="/"||$3=="/usr"||$3=="/var")print;}'
    /dev/hda5 on / type ext3 (rw,errors=remount-ro)
    /dev/vg00/lvol1 on /usr type reiserfs (ro,nodev,noatime)
    /dev/vg00/lvol2 on /var type reiserfs (rw,nosuid,nodev)
    $

    http://www.pathname.com/fhs/
    http://www.pathname.com/fhs/pub/fhs-...ROOTFILESYSTEM
    http://www.pathname.com/fhs/pub/fhs-...HEUSRHIERARCHY
    http://www.pathname.com/fhs/pub/fhs-...HEVARHIERARCHY

    Once you've studied those, hopefully you'll have the answer to your
    question.

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