Splitting partition

skn · 08-14-2009, 05:13 AM

Hello

I am trying to split a partition in two, because i need the free space for another folder. I wanted to avoid rebooting the machine, so I have tried to do it without any partition parograms. The machine is running Red Hat Enterprice linux 5.
I found some usefull information here: http://home.comcast.net/~dckrinke/jan_02_linux.html
I got trough most of it, but got stuck at the end.

The target is /dev/sda2

Code:

Disk /dev/sda: 64 heads, 32 sectors, 17365 cylinders
Units = cylinders of 2048 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/sda1   *         1        50     51184   83  Linux
/dev/sda2            51      9050   9216000   83  Linux
/dev/sda3          9051     11458   2465792   83  Linux
/dev/sda4         11459     17365   6048768    f  Win95 Ext'd (LBA)
/dev/sda5         11459     14530   3145712   83  Linux
/dev/sda6         14531     16578   2097136   82  Linux swap
/dev/sda7         16579     17034    466928   83  Linux

I started by doing a lazy unmount and then used resize2fs to shrink the partition to 2,7GB. Then I deleted the partition using fdisk and created a new one from cylinder 51 - 2765.

The problem is that now I can't create a new partition with free space (cylinders 2766 - 9050).
It will only allow me to create a new partition from cylinder 17035 - 17365.

It this an impossible mission?

unSpawn · 08-14-2009, 07:38 AM

By default a DOS-compatible disk only handles four primary partitions. You have three and the extended partition makes four. You deleted one primary partition and created one primary partition so now you can only created a new logical partition.

skn · 08-17-2009, 04:49 AM

It wont let me create a logical partition with that 5GB.
I solved my problem in another way:
1. I shrunk sda5
2. Moved the swap disk sda6
3. Resized sda7 where i originally needed the extra free space.

I still cant use the 5GB, but I got 1,6GB where I needed it.

jay73 · 08-17-2009, 09:56 AM

You would have to move sda3 to the left so that it takes up the free 5GB. Then you can shrink sda3 to restore it to its original size, which would leave you with 5GB free after sda3. This can be used by moving your logical partition 5GB to the left so that the 5GB now becomes available for a logical partition.

chrism01 · 08-17-2009, 06:25 PM

BTW, in RHEL, after you have used the 'w' cmd to write the new partition table to disk, you can exit fdisk and run 'partprobe', which will force the kernel to read/start using the new partition table without a system reboot.