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Tuesday, December 25, 2012

How to resize or shrink the partition (LVM) in linux or VM

I wanted to shrink LVM partition in VM which has redhat linux and expand root partition because of  memory issue on root partition.  I have done searching excercise in the web and below are the results of the search and best pages that I have seen. However I was not able to reduce the LVM partition as all the procedures mentioned in the below did not recognize the LVM partition created in the redhat linux VM installation. Below procedures are pretty good in general and but does not work for LVM on VM. gparted, parted or steps mentioned below may work other partions. You can try got LVM, it may work for you. I have kept consolidated search result in one page.

http://gparted.sourceforge.net/download.php

http://www.thegeekstuff.com/2011/09/parted-command-examples/
http://gparted.sourceforge.net/screenshots.php#gparted-live-boot-menu
http://en.kioskea.net/faq/2036-how-to-resize-a-partition-using-gparted-on-linux

Back up all your important data before attempting this. Always assume that you can lose all your data when resizing partitions.

Shrink LVM without dataloss

This forum thread suggests the following procedure, in this example we shrink a partition from 10G to 9G:
First, we unmount.
# umount /dev/vg_blah/lv_blah
Check the file system.
# e2fsck -f /dev/vg_blah/lv_blah
Resize the file system.
# resize2fs /dev/vg_blah/lv_blah 9G
Reduce the size of the logical volume.
# lvreduce -L -1G /dev/vg_blah/lv_blah
Shrink the volume group if desired.
# vgreduce vg_blah /dev/sdxy

Thursday, December 20, 2012

How to enable engineering/field test mode in blackberry

Blackberry has a very nice and interesting field test/Engineering mode.
While reading a blog I show that pressing ALT+CAP+H would display usefull  information about your mobile.
But you can enable the engineering mode from this screen using steps metioned in the blog:
http://www.zibri.org/2009/08/hidden-things-are-usually-best.html
Please make sure to follow steps very clearly. Read it twice!

Saturday, December 15, 2012

UMTS Mobile Originated call flow sequence diagram (Mobile to Landline)


UMTS Handover event 2a, 2b, 2c, 2d, 2e, 2f explained

  • Event 2a: Change of Best Frequency.
  • Event 2b: The estimated quality of the currently used frequency is below a certain threshold and the estimated quality of a non-used frequency is above a certain threshold.
  • Event 2c: The estimated quality of a non-used frequency is above a certain threshold.
  • Event 2d: The estimated quality of the currently used frequency is below a certain threshold.
  • Event 2e: The estimated quality of a non-used frequency is below a certain threshold.
  • Event 2f: The estimated quality of the currently used frequency is above a certain threshold.

UMTS Call flow for Mobile to Mobile voice call

This call flow is mainly captured at the RNC.