[SOLVED] It showing 0 for all partition when i add new hard disk

[root@oeis-l03 ~]# fdisk -l

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM

Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1 0 0 Empty
Partition 1 does not end on cylinder boundary.



CAN ANYONE HELP ME TO SOLVE THIS?. I M NEW IN LINUX

All I can offer (at the moment) are a couple of troubleshooting steps to gather more information. Do you have another boot disk (CD or USB perhaps) that you can start up, and then take a look at the drive again. Let us know if you get the same results.

No. Actually my linux machine is hoasted on the VM server. When i created this my Limux VM that time i kept only 20GB hard disk. Now i increased the another hard disk of 20GB.
Then I ran some commands in terminal
fdisk /dev/sdb
fdisk a
1
w

Now when i check the partition it show the following output of newly added disk sdb as
Disk /dev/sdb: 2610 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

Device Boot Start End #cyls #blocks Id System
/dev/sdb1 * 0 - 0 0 0 Empty
/dev/sdb2 0 - 0 0 0 Empty
/dev/sdb3 0 - 0 0 0 Empty
/dev/sdb4 0 - 0 0 0 Empty

I'm assuming that you mean you have a Virtual Machine running. Should I also guess that you are using VMWare? Perhaps if you provided a few other details; like the OS that you are running the Virtual Machine on top of?

My linux OS is Red Hat 5.5
Previously i had 20GB hard disk which is working properly.
Now my requirement is increased and i added another 20 GB hard disk.
Now the hard disks are sda and sdb.
First hard disk 'sda' is working, visible and i m able to do anything here. BUT 2nd hard disk 'sdb' is not yet visible.
I also ran the following commands after adding the 2nd hard disk
fdisk /dev/sdb
fdisk a
1
w
[root@oeis-l03 ~]# fdisk -l

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM

Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1 0 0 Empty
Partition 1 does not end on cylinder boundary.
[root@oeis-l03 ~]#

BUT STILL THIS HARD DISK 'SDB' IS NOT DETECTABLE FOR ME. MAY BE I MISSED SOME 'MOUNT' COMMAND. CAN YOU HELP ME TO SOLVE THIS PROBLEM. TELL ME THE COMMAND

Originally Posted by onkar_nimje I also ran the following commands after adding the 2nd hard disk fdisk /dev/sdb fdisk a 1 w

This isn't correct, it will create an empty type (as you can see from the output you posted). A disk needs to be set up with one ore more partitions, which you did not do.

Try the following:

Start by removing the faulty entry:

fdisk /dev/sdb
d

# you should now have a clean disk
# to create one partition, do the following:

n
p
1
<enter>
<enter>

# check if the new entry is visible
p

# you should see something like this at the bottom (bold parts may differ):
/dev/sdb1    1   999     99999999   83 Linux

# safe the changes and exit:
w

You should now have access to /dev/sdb1

Thanks....
Now i got this correct output

[root@oeis-l03 dev]# fdisk -l
Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM

Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 1 2610 20964793+ 83 Linux
[root@oeis-l03 dev]#

BUT WHEN I M GOING TO CHECK THE DISK SPACE THEN THIS NEWLY ADDED DISK IS NOT COMING IN LIST
see the following output
WHERE IS 'SDB1' WITH 20gb? ITS SHOWING ONLY SDA1

[root@oeis-l03 dev]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
16G 2.3G 13G 16% /
/dev/sda1 99M 17M 78M 18% /boot
tmpfs 2.3G 0 2.3G 0% /dev/shm

You also need to:

1 - create a filesystem on /dev/sdb1
I don't know what you prefer, so this example creates a ext3 journaling file-system:

mke2fs -jv /dev/sdb1

/dev/sdb1 is now ready to be mounted.

2 - mount /dev/sdb1 on a mountpoint
Only you know what this new disk needs to be used for, so the following is just an example:

# create a mountpoint:
mkdir /media/ExtraSpace

# mount /dev/sdb1:
mount /dev/sdb1 /media/ExtraSpace

/dev/sdb1 is now mounted on /media/ExtraSpace, df -h should show this entry.

3 - automated mount during boot
If you want/need this disk to be mounted automatically when booting you need to add an entry in /etc/fstab:

# open /etc/fstab with your editor and add the following at the end:

/dev/sdb1   /media/ExtraSpace   ext3  defaults            0 2

Do remember: /media/ExtraSpace is just an example, change this to your needs.

Thanks a lot...Now i got my full answer...Thank you very much

You're welcome

BTW: Can you put up the [SOLVED] tag (top right hand corner)