Debian – How to resize LVM disk in Debian 8.6 without losing data

debianfdiskresize2fs

I need to resize my first disk (/dev/xvda) from 40 GB to 80 GB. I'm using XEN virtualization, and the disk is resized in XenCenter, but I need to resize its partitions without losing any data. The virtual machine is running Debian 8.6.

Disk /dev/xvda: 80 GiB, 85 899 345 920 bajtů, 167 772 160 sektorů
Jednotky: sektorů po 1 * 512 = 512 bajtech
Velikost sektoru (logického/fyzického): 512 bajtů / 512 bajtů
Velikost I/O (minimální/optimální): 512 bajtů / 512 bajtů
Typ popisu disku: dos
Identifikátor disku: 0x5a0b8583

Device     Boot  Start      End  Sectors  Size Id Type
/dev/xvda1        2048   499711   497664  243M 83 Linux
/dev/xvda2      501758 83884031 83382274 39,8G  5 Extended
/dev/xvda5      501760 83884031 83382272 39,8G 8e Linux LVM

Disk /dev/xvdb: 64 GiB, 68 719 476 736 bajtů, 134 217 728 sektorů
Jednotky: sektorů po 1 * 512 = 512 bajtech
Velikost sektoru (logického/fyzického): 512 bajtů / 512 bajtů
Velikost I/O (minimální/optimální): 512 bajtů / 512 bajtů
Typ popisu disku: gpt
Identifikátor disku: 0596FDE3-F7B7-46C6-8CE1-03C0B0ADD20A

Device     Start       End   Sectors Size Type
/dev/xvdb1  2048 134217694 134215647  64G Linux filesystem

Disk /dev/mapper/xenhosting--vg-root: 38,1 GiB, 40 907 046 912 bajtů, 79 896 576 sektorů
Jednotky: sektorů po 1 * 512 = 512 bajtech
Velikost sektoru (logického/fyzického): 512 bajtů / 512 bajtů
Velikost I/O (minimální/optimální): 512 bajtů / 512 bajtů
Disk /dev/mapper/xenhosting--vg-swap_1: 1,7 GiB, 1 782 579 200 bajtů, 3 481 600 sektorů
Jednotky: sektorů po 1 * 512 = 512 bajtech
Velikost sektoru (logického/fyzického): 512 bajtů / 512 bajtů
Velikost I/O (minimální/optimální): 512 bajtů / 512 bajtů

Best Answer

This should be relatively easy, since you're using LVM:

First, as always, take a backup.
Resize the disk in Xen (you've already done this; despite this, please re-read step 1).
Use parted to resize the extended partition (xvda2); run parted /dev/xvda, then at the parted prompt resizepart 2 -1s to resize it to end at the end of the disk (BTW: quit will get out of parted).
Either (a) create another logical partition (xvda6) with the free space, then:
1. reboot to pick up the partition table changes
2. pvcreate /dev/xvda6
3. vgextend xenhosting-vg /dev/xvda6
or (b)
1. extend xvda5 using resizepart 5 -1s
2. reboot to pick up the partition table changes
3. pvresize /dev/xvda5
Finally, if you want to add that to your root filesystem, lvextend -r -l +100%FREE /dev/xenhosting-vg/root. The -r option to lvextend tells it to call resize2fs itself.

Another option you didn't consider:

Add another virtual disk. If you can do this in Xen w/o rebooting the guest, then you can do this entirely online (without any reboots). Partition the new disk xvdc (this will not requite a reboot, since its not in use), then proceed with pvcreate & vgextend using /dev/xvdc1.

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Resize Root Partition Without Reinstalling Linux – How to Avoid Data Loss

Warning: doing anything to your filesystems without a known-restorable backup is ill-advised.

Do not run any of the following steps if you're not sure your / is clean. If you're not sure, run the following (as root):

# touch /forcefsck

and reboot. This will do an fsck of all your partitions, to be on the safe side.

That being said, since you're using LVM for your root device and an ext3 filesystem, you can extend it online. Before you start make sure you have resize2fs installed. If not, it's usually in a package called e2fsprogs. (If you can't install it because you don't have enough room, try to do a bit of cleanup in /var/log for instance.)

First you extend the underlying volume with (as root):

# lvextend -L+2G /dev/mapper/HU-root

(Adjust the 2G part as you wish - it's the amount of space you want to add.)

Then you need to resize the filesystem. This can be done online with resize2fs:

# resize2fs /dev/mapper/HU-root

This can take a few seconds/minutes. Don't interrupt. Do another reboot at the end, possibly with another /forcefsck, if you want to. It's not necessary, but I often do it anyway.

Resize root lvm partition

No, not safely. From what I have read, the VG must be available (vgchange --available y, but not mounted). I recommend that you boot from a liveCD or USB so that you have tools loaded into memory, but all of your filesystems not mounted.

Check the file system, we don't want to resize something in an inconsistent state

e2fsck -f /dev/s93079-vg/root

Resize the actual filesystem, a little smaller than the final target.

resize2fs /dev/s93079-vg/root 90G

Now, shrink the LVM to the desired size

lvreduce -L 100G /dev/s93079-vg/root

Finally, grow the the root filesystem to match the target LVM volume

resize2fs /dev/s93079-vg/root

While I browsed several guides, the most helpful blog I found on the topic was https://blog.shadypixel.com/how-to-shrink-an-lvm-volume-safely/

Best Answer

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Resize root lvm partition

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