swap | Linuxaria

Review and repair a Linux SWAP Partition

Nov 182013

Original article first published in Spanish on http://vidagnu.blogspot.it/

Yesterday I ran into a problem in a SWAP partition on an Astaro Command Center, so I decided to restart with an Ubuntu CD, and my first attempt to repair the system was with the fsck command, but when trying to use it I got the message fsck.swap: command not found

So I check with the badblocks command that the partition had no bad blocks.

sudo badblocks -v /dev/sda2

The above command did not return any error, then searching the Internet I found this simple way to rebuild a damaged swap partition.

Linux Terminal: Check who uses all your memory with smem

Guides, Pills 6 Responses »

Oct 202013

As system administrator, or simple user that uses Linux on its desktop sometime you notice that something it’s eating all the memory of your system.
As first thing be sure to understand how Linux manage memory, I’ve be called too many time by scared users that did a free and were unable to read its output properly, in short, don’t worry if the Linux Kernel it’s using your memory to cache file.

< rant on >

To my “beloved” users:

Be assured that the Kernel developers can do a better job than you (and me) in find a good algorithm to cache file and free that memory area when a process need it, so please don’t ask me to put in cron some job that run something like that :

echo 3 > /proc/sys/vm/drop_caches

After that you’ll have more free memory available on the system, true, but the system will have to re-read all the files from the disk, so in terms of performance this is usually a bad move.

< /rant >

But now let’s take a look at a nice small program that can help us in find which process/users are using, for real, the memory of our systems.

Linux memory management

Guides 10 Responses »

Jun 222012

Image from http://www.linuxatemyram.com/

I think that is a common question for every Linux user soon or later in their career of desktop or server administrator “Why Linux uses all my Ram while not doing much ?”. To this one today I’ve add another question that I’m sure is common for many Linux system administrator “Why the command free show swap used and I’ve so much free Ram ?”, so from my study of today on SwapCached i present to you some useful, or at least i hope so, information on the management of memory in a Linux system.