IT Dribble

Well before you power to replace the disk - can you be sure it will power back on?
Some distros have the bad habit of only install GRUB to one physical disk and if that disk dies…RAID wont save you (but a boot CD will…)

Firstly I like to confirm if /boot is configured in RAID 1. I then usually also install GRUB to all the physical disks via:

grub-install /dev/sda

and sdb and sdc etc. Then I power off the server and replace the disk.

After powering on the server, sometimes it won’t boot due to the new disk getting booted first, so make sure to select another disk in the BIOS boot-up menu.

After the operating system returns it’s a matter of recreating the partitions on the new disk, before trying to add it back into the RAID array. My servers all have the same disk sizes in the array and the same partition layouts, so to recreate them on the old disk I just perform:

sfdisk -d /dev/existing-disk | sfdisk /dev/new-disk

Confirm the new disks get the correct layout via:

cat /proc/partitions

and then add the partition back to the RAID array:

mdadm --add /dev/mdX /dev/sdXX

And then finally confirm its rebuilding via:

mdadm --detail /dev/mdX

OR

cat /proc/mdstat

I had the task of rebuilding an Astaro UTM 220 with CentOS and the LCD panel looked so lifeless, So I decided to restore it to some version of functional! From my research I can see that the display is LCM-162 and utilises the lcd driver HD44780.

In a nut shell here is what I did:

• Download LCDproc (http://lcdproc.omnipotent.net/)
• Modify: lcdproc-0.5.6/server/drivers/hd44780-ext8bit.c

Change:

#define RS  STRB
#define RW  LF
#define EN1 INIT 

To:

#define RS  SEL
#define RW  INIT
#define EN1 LF 

• compile it with option: ‘./configure –enable-drivers=hd44780′
• make && make install
• Modify: /usr/local/etc/LCDd.conf

Change:

• Line 53: Driver=hd44780
• Line 502: ConnectionType=8bit
• Line 509: Device=/dev/parport0
• Line 544: Size=16×2

Test it:

LCDd -f -r 4 -c /usr/local/etc/LCDd.conf &

lcdproc -f -s localhost -p 13666 C M L

If it works its just a matter of copying: scripts/init-LCDd.rpm and scripts/init-lcdproc.rpm to /etc/init.d and configuring chkconfig properly.

Hopefully that helps.

1. Open Admin command prompt or powershell
2. Remove the unused KMS key: slmgr -upk
3. Install your MAK key: slmgr -ipk XXXX-XXXX-XXXX-XXXX
4. Activate Windows

For a raw filesystem try:

fdisk -l harddrive.img
mount -o ro,loop,offset=xxxxxxxxx harddrive.img /mnt/loop

or for filesystems with volume groups etc try:

losetup /dev/loop0 disk.img
kpartx -a /dev/loop0

Then to mount the first partition:

mount /dev/mapper/loop0p1 /mnt

Or to activate the volume group then mount the logical volume:

vgscan
vgchange -ay vg
mount /dev/vg/lv /mnt

Hope that helps.

It seems that Nagios is logging in two places on my CentOS 7 build.
Once in /var/log/nagios/nagios.log and also in /var/log/messages.

Considering I like my builds nice and tidy and don’t want contamination of my log files, I needed to filter out Nagios using rsyslog.

Because rsyslog processes it’s rules in order, we need to insert the following rule

# Stop nagios going into messages - it already has a log
if $programname == 'nagios' then stop

before:

# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none                /var/log/messages

Then restart rsyslogd!