When you try to unmount a device sometimes you get this error: /media/sdxy: device is busy when you need to unmount a CD drive or to remove an external drive or anything else.The ideal situation is when your Linux is telling you what is keeping the device busy, but is not happening.

This is how to properly use umount command:

When you get this error,

# umount /media/sdxy
umount: /media/
sdxy: device is busy
umount: /media/
sdxy: device is busy

1. First thing you’ll probably do is to use fuser to find out what process is keeping your device busy. You can do it like this:

# fuser -m /dev/sdxy
/dev/sdxy: 230452
# ps -aux | grep 230452
root     230452  0.2  0.0  20756  3764 pts/0    Ss   22:35   0:00 -bash

You need to kill the 230452 process then umount the drive.

2. The second way to umount your drive is to use the -l argument from umount command. This is short for Continue Reading…

Many sysadmins think about performance tunning as optimizing loops, memory use, algorithms, etc.But you don’t get a massive performance gains from optimizing CPU and memory use, but from eliminating I/O calls.

CPU, bandwidth, and memory strangulation is turning into additional and additional common on shared servers and virtualization systems, but practical disk throttling isn’t even on the horizon from what I can tell. Improper I/O usage from any app affects everybody.

Step1. Edit /etc/fstab file and add noatime for your root file system:

vim /etc/fstab

And then add noatime after errors=remount-ro

cat /etc/fstab
# /etc/fstab: static file system information.
# Use ‘blkid’ to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=136c3e1f-523e-40f3-b5cb-7ab634b16c18 /               ext3    errors=remount-ro,noatime 0       1
# swap was on /dev/sda5 during installation
UUID=48802a17-2ec4-4d08-942f-e56a438e7c6b none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0 Continue Reading…

There are several methods to move Linux to another hard disk on the same server.
But I used Unix dump / restore utility to do this …

Step1. First you need a new hard disk partition in the same way as with previous unit (Linux is running on). I usually use the utility ‘fdisk‘.
Let us suppose that the old drive is /dev/sda and a new one is /dev/sdb.
To view the partition table hda please run ‘fdisk-l  /dev/ sda “which should show something like this:

root@deb:~# fdisk -l /dev/sda

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0007384e

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        9330    74936320   83  Linux
/dev/sda2            9330        9730     3212289    5  Extended
/dev/sda5            9330        9730     3212288   82  Linux swap

Step2. After this run ‘fdisk /dev/sdb’ and make the same partitions at it. Interactive mode of fdisk utility is well documented and is very intuitive, so I don’t think it would be difficult to perform partitioning.

After this is done, we should make new filesystems at partitions we’ve created:

mkfs -t ext3 /dev/sdb1
mkswap /dev/sdb2

Step3. Now new hard drive preparation is finished and we can proceed with moving Linux to it. Mount new filesystem and change directory to it:

mount /dev/hdb1 /mnt/hdb1
cd /mnt/hdb1

Step4.  Perform moving by command:

dump -0uan -f – / | restore -r -f

When dump/restore procedures are done we should install boot loader to new HDD. Run ‘grub’ utility and execute in it’s console:

root (hd1, 0)
setup (hd1)


Linux machines are  aware in the case of security. This extra security may sometimes become a headache for simple linux users.

For example, if u have separate partitions or hard drives , every time you have to mount those when required.The time-saving solution is to mount such media permanently.

Firstly to tell Debian where to find the mount and where you want it mounted. Secondly, to create the folder within Debian’s recognised file structure to house the mounted media. After you perform this configuration, your backup folder on a secondary disk can be accessed from within your /home/user folder.

1. Open the fstab file that controls your mounts:

nano etc/fstab

2.Find out the name of partition that you are planning to mount . It lists recognized partition tables:

fdisk -l

Continue Reading…

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