21 July, 2009

Notes on various small tweaks

Note 1: Console properties
To change the console configuration (e.g. language switching etc.etc.)
dpkg-reconfigure console-setup

also for locales the old "debian" way of selecting the locales (via a menu) is not used. Rather one
has to do it manually (Check various easy guides on the web for more information).

Note 2: Dont' Zap
To be able to restart the X server with Alt+Ctrl+Backspace (this has changed recently following a
decision by Xorg maintainers). To restore this functionality do:
1. Edit xorg.cong and add

Section "ServerFlags"
        Option  "DontZap"       "False"

2. or  (in ubuntu)
dontzap --disable

both have the same effect, i.e. they modify the xorg.file.

Note 3: MDADM
To configure mail notifications I had to enter my e-mail. The easiest way is:
dpkg-reconfigure mdadm
and run it as a deamon...

Note that it is a wise choice to have it run a consistency check (which might be time consuming but nevertheless it is useful).

Alternatively, you can manually edit the file

Now to test it we need to simulate a drive failure. I will simulate a failure on my raid1 (md1) array (since it is easier to rebuild)
 mdadm --manage --set-faulty /dev/md1 /dev/sdb1
and then to see that it failed try:
mdadm --detail /dev/md1
cat /proc/mdstat

You should now have received an e-mail notifying you of the failure.
Remove the failed drive:
mdadm /dev/md1 -r /dev/sdb1
and re-add it:
mdadm /dev/md1 -a /dev/sdb1
and verify that everything is back to normal.

Note 4: Configure smartmon tools
Verify that the packages mail (or mailx) and smartmontools are installed

1) Edit the file /etc/smartd.conf (see the man page for the available options)

*  Comment out the DEVICESCAN live

* and add the following 
# Run a Long self test on the 13th of each month and short self tests on Wednesday evenings.
# -a: Run default tests
# -m: root (Mail to root)
/dev/sda -d sat  -s (L/../13/./01|S/../../3/01) -a -W 4,47,55 -m root
/dev/sdb -d sat -s (L/../13/./02|S/../../3/02) -a -W 4,47,55 -m root
/dev/sdc -d sat -s (L/../13/./03|S/../../3/03) -a -W 4,47,55 -m root
/dev/sdd -d sat -s (L/../13/./04|S/../../3/04) -a -W 4,47,55 -m root
/dev/sde -d sat -s (L/../13/./05|S/../../3/05) -a -W 4,47,55 -m root
/dev/sdf  -d sat -s (L/../13/./06|S/../../3/06) -a -W 4,47,55 -m root

2) Edit /etc/default/smartmontools
and uncomment the line: (to start the deamon)

3) Restart the deamon...
/etc/init.d/smartmontools restart

and check /var/log/syslog if everything works as expected

Note 5: To receive automatically various notifications.
Edit /etc/aliases (of course we need something like sendmail) installed and configured.
Edit  /etc/aliases

add the line
root: name@mailadd.com

and run newaliases

Note 6: Other rc.local options

Here we can add various optimizations. For example

Note 7: Disable ipv6


Note 8: Logwatch


Note 9: prefetch and readahead

Note 10: APC UPS (Configuration and notifications).

Note 11: Sensors

Note 12: Sound Card

Note 13: Sudoers

Run visudo as root and add the lines:

# User privilege specification
root    ALL=(ALL) ALL
username   ALL=(ALL) ALL

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