mount /unmount

[Matthew Seaman]

On 04/07/2011 13:28, tethys ocean wrote:
> is FreeBSD can boot and run all service while one of slice is not mount for
> example /usr slice..

You can't run a program unless the partition containing it is mounted.
Neither can you run a program if any command interpreter (eg. perl, php,
bash) it uses, or any shared library is similarly not on a mounted
partition.

In order to facilitate working in single user mode, where just about
every partition except the root is usually unmounted, there is a
selection of useful applications in /rescue -- these are statically
linked so no problems with unavailable shlibs.

> and second question is my mysql is in /var slice if /var is not mout can I
> access mysql being root and chek all databases also can read log file on
> /var

MySQL's default data directory location is /var/db/mysql on FreeBSD.
No, you need to mount /var to verify the information you require.

> third question is can I mount any unmount slice by using just fsck  :)

If a partition was not unmounted cleanly (eg. the machine crashed, or
the power was cut off suddenly) then fsck(8) should be used to check and
fix any problems on the filesystem.  If you've booted into single-user
mode, then definitely fsck any partitions before trying to mount them.

However, any fsck'ing that the system requires should happen
automatically if you just let the system reboot itself.  It's only
occasionally when there are certain problems that fsck needs human input
to resolve that you will be instructed to get onto the console and run
fsck by hand[*].

Generally you'ld then use mount(8) to mount any partitions.

	Cheers,

	Matthew

[*] This is dependent on what sort of filesystems you are using.  For
instance, ZFS never needs to stop and fsck in this way.  UFS+Journal
won't need it either[+].

[+] Sysinstall doesn't support installing a system using these
filesystem technologies: it can be done manually, but that isn't for the
faint of heart.

-- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW

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