Wednesday, July 25, 2012

Creating local directory for yum installation using createrepo @ rhel ,fedora

To create a local directory from which we can install through yum,Mainly we need the "createrepo plugin of yum"

first make the directory

>mkdir pak

then copy the rpms into the directory

then use createrepo to create the repository files inside the folder

>createrepo pak

then it will make repository files and show following on success

Saving Primary metadata
Saving file lists metadata
Saving other metadata

then make a file @ /etc/yum.repos.d/pak.repo

>vim /etc/yum.repo.d/pak.repo

inside that we need name url and enable option
enable should be equal to 1 to make the repository
active all the time.the url will have destination to
the folder

as follows


[pal]
Name=pak $releasever $basearch local repository
baseurl=file:///pak
enabled=1

Sunday, July 22, 2012

fedora 17 and grub2

Fedora 17 and grub2...While installing fedora 17 from the live cd  at the end of finishing the installations i got an error like "installing bootloader failed ..system any not boot properly " the problem was maily with grub2 version .Even though the grub2 is much better than the older one it has some bugs .it shows some problem whiling installing to a system with older grub.

We can try reinstall the grub with the distro dvd rescue mode...

1.chroot  /mnt/sysimage

the root file system will be loaded to /mnt/image

2. grub2-install /dev/sda
installing the grub to ur harddisk ..in normal mode this wont work we should also give --force and --recheck

grub2-install --force --recheck /dev/sda

3.to get all the operating system use

grub2-mkconfig -o /boot/grub2/grub.cfg

the -o will create the config file

 

 

Saturday, July 14, 2012

To create keyboard shortcut for terminal in linux

open the terminal then type

>gnome-keybinding-properties

Then an window will pop up that window can be used to create custom keyboard shortcuts.

Click add and give name for the entry and terminal command which should be activated with shortcut and click Apply

now in the window backward an entry such as custom entry will appear and now click in shortcut then the disabled option changes to New shortcut .now press the needed shortcut it will be set.

command for terminal is gnome-terminal and give needed shortcuts

Resizable linux partions --LVM-logical volume management

In linux we can can create resizable partition  which can be resized if free space is available. That type of partitions logical volumes.
lvm-digram

1.-------->First we need to create normal logical partitions.
i have a partion  /dev/sda4  in /dev/sda
2.--------->Then we need to select the partition and change the partition type to 0x8e or create the partition as physical volume using given option in palimpsest
using fdisk command we could change the partion type to 0x8e . we could use the 't' option in fdisk to change the type ,after seleting the 't' option it will prompt for the partition no of which type need to be changed .using the 'l' option will list types of  partition type.
fdisk /dev/sda
At the Linux fdisk command prompt,

  1. press n to create a new disk partition,

  2. press p to create a primary disk partition,

  3. press 1 to denote it as 1st disk partition,

  4. press ENTER twice to accept the default of 1st and last cylinder – to convert the whole secondary hard disk to a single disk partition,

  5. press t (will automatically select the only partition – partition 1) to change the default Linux partition type (0×83) to LVM partition type (0x8e),

  6. press L to list all the currently supported partition type,

  7. press 8e (as per the L listing) to change partition 1 to 8e, i.e. Linux LVM partition type,

  8. press p to display the secondary hard disk partition setup. Please take note that the first partition is denoted as /dev/hdb1 in Linux,

  9. press w to write the partition table and exit fdisk upon completion.


3.-------->Next, this LVM command will create a LVM physical volume (PV) on a regular hard disk or partition:
pvcreate /dev/sda4

4---------->Now, another LVM command to create a LVM volume group (VG) called vg0 with a physical extent size (PE size) of 16MB:
vgcreate -s 16M vg0 /dev/hdb1

 

5---------->Create a 400MB logical volume (LV) called lvol0 on volume group vg0:
lvcreate -L 400M -n lvol0 vg0

This lvcreate command will create a softlink /dev/vg0/lvol0 point to a correspondence block device file called /dev/mapper/vg0-lvol0.

6----------->Formatting the partition to the needed type ..here i am going to format it to ext4 type

mkfs.ext4 /dev/vg0/lvol0
Finally mounting the partition to the needed place.here i will be mounting the partition to /data

mkdir  /data

mount /dev/vg0/lvol0 /data

some of the useful commands in this are

pvs

vgs

lvs

pvdisplay

vgdisplay

lvdisplay

more useful commands are lvextend and lvreduce

reduced should be used carefully because  cutting of the file system may cause data loose if not done properly