I haven’t been working on my new kvm virtualization setup in over a month becasue I’ve been working on my condo to sell in the spring. I took down my entire physical work enviroment to paint the walls and also as a basic cleaning out measure. I finally moved my old mac pro to a place where I can get it on the network without running any cables and I’ve begun where I’ve left off last.
The mac pro, as you remember, had ubuntu linux instaled on it and it has become my kvm host. There are three disks in the machine, I’ve only been using one until now. I want to add the other disks and I want the best performance and I’m not concerned about redundancy, so I’ve decided to stripe the disks. First off let’s look at the current environment:
root@kvm:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/kvm--vg-root 283G 44G 225G 17% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 5.4G 4.0K 5.4G 1% /dev
tmpfs 1.1G 676K 1.1G 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 5.4G 0 5.4G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sda2 237M 37M 188M 17% /bootI’ve go two more disks, you can see them with a fdisk -l. I won’t show all of the output here, but I will show you one of my disks (/dev/sdc), first I delete the current partition(s) then I create a new partition.
root@kvm:~# fdisk /dev/sdc
WARNING: GPT (GUID Partition Table) detected on '/dev/sdc'! The util fdisk doesn't support GPT. Use GNU Parted.
Command (m for help): p
Disk /dev/sdc: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sdc1 1 625142447 312571223+ ee GPT
Command (m for help): d
Selected partition 1
Command (m for help): p
Disk /dev/sdc: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-625142447, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-625142447, default 625142447):
Using default value 625142447
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.Let’s take a look at the current volume group, if this doesn’t work for you then LVM is not being used.
root@kvm:~# vgdisplay
--- Volume group ---
VG Name kvm-vg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 297.85 GiB
PE Size 4.00 MiB
Total PE 76249
Alloc PE / Size 76245 / 297.83 GiB
Free PE / Size 4 / 16.00 MiB
VG UUID dDekzp-hOYb-0iHn-xvwR-JMpG-C7tE-4xqttiNow let’s extend the volume group over the two new disks:
root@kvm:~# vgextend kvm-vg /dev/sdb1
No physical volume label read from /dev/sdb1
Physical volume "/dev/sdb1" successfully created
Volume group "kvm-vg" successfully extended
root@kvm:~# vgextend kvm-vg /dev/sdc1
No physical volume label read from /dev/sdc1
Physical volume "/dev/sdc1" successfully created
Volume group "kvm-vg" successfully extendedLet’s check df -h again:
root@kvm:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/kvm--vg-root 283G 44G 225G 17% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 5.4G 4.0K 5.4G 1% /dev
tmpfs 1.1G 676K 1.1G 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 5.4G 0 5.4G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sda2 237M 37M 188M 17% /bootWait, it’s not there, what’s going on? Let’s run lvdisplay:
root@kvm:~# lvdisplay
--- Logical volume ---
LV Path /dev/kvm-vg/root
LV Name root
VG Name kvm-vg
LV UUID V5jemW-z51Z-4Mlx-zyR2-ZAtJ-Hzcz-ETmKP6
LV Write Access read/write
LV Creation host, time kvm, 2014-08-06 20:38:36 -0400
LV Status available
# open 1
LV Size 286.84 GiB
Current LE 73431
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:0
--- Logical volume ---
LV Path /dev/kvm-vg/swap_1
LV Name swap_1
VG Name kvm-vg
LV UUID MHvSXV-OhFS-YSWs-6C8Z-SeIL-xMpS-1anUC1
LV Write Access read/write
LV Creation host, time kvm, 2014-08-06 20:38:36 -0400
LV Status available
# open 2
LV Size 10.99 GiB
Current LE 2814
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:1root@kvm:~# lvextend /dev/kvm-vg/root /dev/sdb1
Extending logical volume root to 287.32 GiB
Logical volume root successfully resized
root@kvm:~# lvextend /dev/kvm-vg/root /dev/sdc1
Extending logical volume root to 585.41 GiB
Logical volume root successfully resizedroot@kvm:~# lvdisplay
--- Logical volume ---
LV Path /dev/kvm-vg/root
LV Name root
VG Name kvm-vg
LV UUID V5jemW-z51Z-4Mlx-zyR2-ZAtJ-Hzcz-ETmKP6
LV Write Access read/write
LV Creation host, time kvm, 2014-08-06 20:38:36 -0400
LV Status available
# open 1
LV Size 585.41 GiB
Current LE 149865
Segments 3
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:0
--- Logical volume ---
LV Path /dev/kvm-vg/swap_1
LV Name swap_1
VG Name kvm-vg
LV UUID MHvSXV-OhFS-YSWs-6C8Z-SeIL-xMpS-1anUC1
LV Write Access read/write
LV Creation host, time kvm, 2014-08-06 20:38:36 -0400
LV Status available
# open 2
LV Size 10.99 GiB
Current LE 2814
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:1Good, it’s there, let’s try df -h again:
root@kvm:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/kvm--vg-root 283G 44G 225G 17% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 5.4G 4.0K 5.4G 1% /dev
tmpfs 1.1G 676K 1.1G 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 5.4G 0 5.4G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sda2 237M 37M 188M 17% /bootDammit it’s still not there. We need to run resize2fs:
root@kvm:~# resize2fs /dev/kvm-vg/root
resize2fs 1.42.9 (4-Feb-2014)
Filesystem at /dev/kvm-vg/root is mounted on /; on-line resizing required
old_desc_blocks = 18, new_desc_blocks = 37
The filesystem on /dev/kvm-vg/root is now 153461760 blocks long.df -h one more time:
root@kvm:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/kvm--vg-root 577G 44G 507G 8% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 5.4G 4.0K 5.4G 1% /dev
tmpfs 1.1G 676K 1.1G 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 5.4G 0 5.4G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sda2 237M 37M 188M 17% /bootPerfect.