zswap – compcache, compressed swap for better performance

2013-11-17 2 min read Linux

First, here is a link to article on compcache.

http://code.google.com/p/compcache/wiki/CompilingAndUsingNew

zswap is already in the kernel and you can see the documentation in the kernel documentation. Here is the name of the file if you need:

/usr/share/doc/kernel-doc-$(uname -r)/Documentation/vm/zswap.txt

Here is the overview, in case you do not want to install kernel-doc

Overview:

Zswap is a lightweight compressed cache for swap pages. It takes pages that are
in the process of being swapped out and attempts to compress them into a
dynamically allocated RAM-based memory pool. zswap basically trades CPU cycles
for potentially reduced swap I/O. This trade-off can also result in a
significant performance improvement if reads from the compressed cache are
faster than reads from a swap device.
Continue reading

force recheck on reboot – fsck

2013-09-27 1 min read Linux

If you want to force a fsck re-check on reboot, then just

touch /forcefsck

Set some disk params to be safe

2013-09-05 3 min read Fedora Linux

It is always “Better safe than sorry” so, here are some things you
should do..

First check fstab, if you have partitions other than root then use UUID instead of device:

UUID=a8f13a0d-3f1f-42e4-b076-f44b4163306c /mnt/Backup     ext4 defaults,relatime 1 2

Then entries for all your mounts should be like above.
Points to note here :

Disk is mounted using the UUID and not with /dev/sdXX. This ensures
that even if your disk ids change, you will be able to mount them. To
get the partition UUID, you can execute :

rpmconf – Tool to handle rpmsave and rpmnew files

2012-06-18 1 min read Bash Fedora

Install the utility:

sudo yum install rpmconf

Description:

Description : This tool search for .rpmnew, .rpmsave and .rpmorig files and ask you what to do

with them:

Keep current version, place back old version, watch the diff or merge.

And finally run the utility:

sudo rpmconf -a

and if there is a conflict or rpmsave or rpmnew file, then you will see something like this:

Upgrade to Fedora 17 from 16.

2012-05-15 1 min read Fedora

As usual time in couple of days to upgrade to Fedora 17. Release schedule is for 05/22 and so its just around the corner. So, if you are looking at upgrading using yum, then make sure that you visit this page.

There are some changes in latest version that will not allow you to upgrade without executing few commands manually and that page lists them. And if you are too brave and just want the steps and the command then here it is:

Introducing /run – what is this directory doing in my root directory?

2011-04-13 1 min read Linux

http://lwn.net/Articles/436012/

There is a suggestion to add /run directory that will be mounted as tmpfs. This directory will be mounted early in the boot process and can be used in various scenario’s. I hope this will improve few things in the linux world.

How to find the number of files inside the directory in linux (manivasagan.wordpress.com)
How do you reset your Ubuntu password (wiki.answers.com)
Finding Files using – locate – on Linux (galigio.org)