Blogs

To receive local root email to an externally monitored email address:

• Login to plesk control panel and set the admin contact email address for the server which should update "/var/qmail/alias/.qmail-root" file and add an alias for root.
  
• Either add the hostname (FQDN) to the qmail control locals file or to the virtualdomains file located in "/var/qmail/control/".
  
• Also add the hostname (FQDN) to the "/var/qmail/control/rcpthosts" file if not already present so local mails get delivered.
  
• Restart inetd and qmail:
  
  /etc/init.d/inetd restart
/etc/init.d/qmail restart
• Check with:
  
  /var/qmail/bin/qmail-showctl

  This should show:
  

  ...
locals:
...
Messages for host.domain.tl are delivered locally.
...
rcpthosts:
...
SMTP clients may send messages to recipients at host.domain.tld.
...

HDD Temperature

You can usually identify which hard disks are on your system by looking in "/proc/ide" and in "/proc/scsi".

`fdisk -l` lists the two drives as "sda" and "sdb".

With the upgrade to drupal-5.14 and using the SecurePages 5.x-1.7-beta1 module:

Error:

Solution:
Added the below code to the beginning of the securepages_init function in "securepages.module" so function gets loaded.

  if (!function_exists('drupal_urlencode')) {
    include_once 'includes/common.inc';
  }

Reference:
http://drupal.org/node/330171

Default to highlighting search string when using grep by adding the below alias to ~/.bashrc file:

1. Start screen using the command:
   $ screen -S <SessionName>

   The -S switch gives the session a name, which makes multiple screen sessions easier to manage.

2. Allow multiuser access in the screen session:
   CTRL-A
:multiuser on

3. Grant permission to the guest user to access the screen session:
   CTRL-A
:acladd <guest_user>

4. The guest user can now connect via:
   $ screen -x <host_user>/<SessionName>

With the recent update of uw-imap from epel repository to uw-imap-2007d-1.el5, I was getting the below error which indicated that uw-imap required 2007d version of c-client.

Below was the error message as logged in "/var/log/messages":

Adding "libc-client2007" to the list of "includepkgs" in yum conf for epel repository and doing a `yum update` resolved the issue by updating libc-client2007-2007b to libc-client2007-2007d.

Munin is network monitoring tool for servers. It uses RRDTool, an open source used to generate graphics and logging server activities.

I am installing and configuring munin on centos 5 x86_64 using yum.
1)First of all, we need to add a RPMforge repository.

2)Installing yum

3)chaning the ownership of munin web docroot to munin, as by default it goes to root.

I have outlined below the steps taken to move from a normal single disk system and convert to a raid1 using an additional drive:

Note: /boot cannot be on lvm nor any other raids other than raid1 partition.

Don't forget to make the essential backups prior.

Convert / to raid/lvm

1. fdisk /dev/sdb and make clone of sda (convert partition type to "Linux raid autodetect")
   
2. add /dev/sdb1 -- /boot - 13 blocks (100Mb) - type raid
   
3. add /dev/sdb2 -- rest - type raid
   
4. Create raid partitions:
   
   partprobe
mdadm -C /dev/md0 --auto=yes -l 1 -n 2 missing /dev/sdb1
mdadm -C /dev/md1 --auto=yes -l 1 -n 2 missing /dev/sdb2
5. Create logical volume and copy / partition and /dev files over:
   
   pvcreate /dev/md1
vgcreate vg0 /dev/md1
lvcreate -L 4G -n lv0 vg0
mke2fs -j /dev/vg0/lv0
mkdir /mnt/lv0
mount /dev/vg0/lv0 /mnt/lv0
find / -xdev | cpio -pvmd /mnt/lv0
cp -aux /dev /mnt/lv0
6. Edit /mnt/lv0/etc/fstab to reflect the new root
   
   /dev/vg0/lv0            /                       ext3    defaults        1 1
7. Chroot to new filesystem and create initrd with raid and lvm support
   
   mount --bind /dev /mnt/lv0/dev
chroot /mnt/lv0
mount -t proc /proc /proc
mount -t sysfs /sys /sys
vgscan
vgchange -ay
mkinitrd -v /boot/initrd-`uname -r`.lvm.img `uname -r`
umount /sys
umount /proc
exit
mv /mnt/lv0/boot/initrd-`uname -r`.lvm.img /boot
8. Edit grub.conf to point to new root /dev/vg0/lv0
   
9. reboot

Convert /boot to raid1

When converting from IDE to AHCI in the BIOS to include additional drives, I would get a kernel panic... as by default the bios was setup with the drives as IDE.

Booted using existing IDE and created a new kernel image with support for AHCI via the --preload option to manually specify modules support:

Then create a new grub boot option to load the new custom kernel image and select it when grub boots up using AHCI.

Recently, I've noticed that in ubuntu (6.06) dapper server with apache-2.0.55, apache by default listens to IPv6, thus was causing slow response times. The response times was much improved by having apache listen to IPv4 instead.

Edit /etc/apache2/ports.conf and specify an IPv4 address on all Listen directives: