howto mirror a volume group

mirroring is a raid technique where all data on the first disk is mirrored identically on the file on a second disk. the advantage of any raid technique is visible when a disk goes bad, but your data is still safe and you have the opportunity to replace the bad disk.
in our example we are going to mirror rootvg. note that rootvg has some additional steps to use the 2nd disk in a disaster situation. on AIX unless you are doing some sort of custom configuration rootvg is on hdisk0

1. extend the rootvg to the second disk

howto extend lv in aix

Extending a filesystem on AIX is similar to linux. you add the physical disk to the system. you convert the physical disk to a physical volume (pv) then you add the pv to the volume group (vg) then you extend the logical volume (lv) with the newly assigned space. then you extend the filesystem on the lv.

in the following example we want to add 1Gb to /home/user1. where /home/user1 is an lv by itself. the most common use is normally /oracle in the enterprise (or /u01 or wherever you installed oracle) or /home on the home desktop.

and here are the commands:

howto extend the logical volume in linux

Recently, I added a new hard disk to my linux box and I decided to document it the process of how to extend to root partition over the 2 disks.

First of all the disk was the 2nd disk on the system so it was /dev/sdb

so we do a

pvcreate /dev/sdb

then we add this new pv we created to an already existing lv. for the purposes of this document let us call it lv_root


sometime back, i was building an oracle rac with oracle linux 5.x when i discovered on the same dvd an rpm by the name of oracle-validated. this link is the first introduction of the world to the rpm.

howto fix 0315-180 logread: UNEXPECTED EOF on errpt log

so i was trying to view the error report for an aix machine but i got some unexpected output.

# errpt -a
0315-180 logread: UNEXPECTED EOF
0315-171 Unable to process the error log file /var/adm/ras/errlog.
0315-132 The supplied error log is not valid: /var/adm/ras/errlog.

the steps below are what i did to fix it courtesy of ITToolBOX

switching user

following the very essential (and blasphemous) concept "root is god". any decent system administrator will never ever log in as root directly. instead the SA should log in as his normal user account and then switch user to run the command as root

switching user can be done in 2 ways:

su -c <command>
sudo <command>

the question arises: what's the difference?

howto: setup a tethered router network aka internet connection for laptop via pc via android phone

it came to pass on one cold, snowy night that internet access from only one compute was no longer sufficient. i needed to put my old laptop on the internet too. however, my internet source was my t-mobile android phone. yes, i tether my pc or laptop to get on the internet. this brings up an interesting scenario because the android phone's usb cable has to go into a usb port, either on the laptop or the pc.

so there are 3 devices in this network

howto: fix superblock last mount time error

sometime during the middle of the night, the electricity cut out. thats normally not a problem, but this time it was because apparently my cmos battery died. so all my bios settings died and some other items that depend on the cmos battery.

anyways i sat down and reconfigured my bios as much as i remembered (does anybody document changes to the bios?!) then started up my pc, assuming all was well.

actually, no i got this message which i noted down

howto: dansguardian for fedora

for a while now, i have been looking for a content filtering system for my own personal use. i did a little bit of research and i came up with dansguardian + squid. the original documentation is from James Japan's site l the documentation as is works great. great for a standalone pc. which was my original requirement.

howto: configure smstools on fedora

smstools3 is a command line tool to send sms via your gsm modem. version3 has a new maintainer keke who i must say is very helpful. and over the weekend helped me get smstools to send messages.


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