Debian in a VMware VM and LVM
Hi,
I have been using Linux for several years but now I have another learning moment. ;-) I have read several LVM howto sites but still run into things I do not understand.
Can someone please answer the 4 embedded questions and tell me what I(?) did wrong.
Using the 6.0.4 amd netinst CD I created a small 10GB virtual machine (VM). I then realized I needed it to be a bit bigger so I wanted to extend the LVM environment and add that space to the /var logical volume.
Of course as this is a new VM I just could have started from scratch but I am trying to learn something as well. ;-)
First I had a look at the current disk layout using fdisk -l
root@wwwgw:~# fdisk -l
Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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: 0x000d6e97
Device Boot Start End Blocks Id System
/dev/sda1 1 37 291840 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 37 1306 10190849 5 Extended
/dev/sda5 37 1306 10190848 8e Linux LVM
1)
Why the warning about the 300MB /boot partition not ending on a cylinder boundary? I used the manual setup in the Debian 6.0.4 installation and told it to create a 300MB partition at the beginning of the disk. Did the installation software do something wrong or should I have know something I do not know yet?
2)
After that came a lot of warnings about /dev/dm-0, /dev/dm-1, /dev/dm-2, /dev/dm-3 and /dev/dm-4. I know those are LVM2 devices but...
Why is fdisk (still) seeing them as disks/partitions it has to show during a listing, and then complain they are not valid?
At the VMware level I increased the disk from 10GB to 12GB. Using cfdisk, which in my opinion gives less cause for a user error, I created a new logical sda6 partition in the free space. The end result is:
root@wwwgw:~# fdisk -l
Disk /dev/sda: 12.9 GB, 12884901888 bytes
255 heads, 63 sectors/track, 1566 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: 0x000d6e97
Device Boot Start End Blocks Id System
/dev/sda1 1 37 291840 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 37 1566 12285008 5 Extended
/dev/sda5 37 1306 10190848 8e Linux LVM
/dev/sda6 1306 1566 2094127+ 8e Linux
3)
Why is there a + at the end of the number of blocks?
I then want to make the sda6 partition a LVM physical volume using
root@wwwgw:~# pvcreate /dev/sda6
Device /dev/sda6 not found (or ignored by filtering).
root@wwwgw:~#
indeed, there is no /dev/sda6 yet.
4)
Why is /dev/sda6 not there yet? What step am I missing?
Ok, after a reboot (it is not a production server yet) the /dev/sda6 is there.
Form here on it was (almost) straight sailing. ;-)
root@wwwgw:~# pvcreate /dev/sda6
Physical volume "/dev/sda6" successfully created
root@wwwgw:~# vgextend vgroup1 /dev/sda6
Volume group "vgroup1" successfully extended
Then to runlevel 1 to make sure (almost) nothing is using the /var directory tree
and
root@wwwgw:~# lvextend -l+2G /dev/vgroup1/lvvar
Extending logical volume lvvar to 3.86GiB
Logical volume lvvar successfully resized
root@wwwgw:~# umount /var
Then first a filesystem check as that seems to be needed before resizing. Not doing so will give me a warning although this was not mentioned in the HOWTOs I have read.
root@wwwgw:~# fsck -f /dev/vgroup1/lvvar
root@wwwgw:~# resize2fs /dev/vgroup1/lvvar
root@wwwgw:~# mount /var
and back to runlevel 2
Anything else I missed?
Bonno Bloksma
Reply to: