Difference between revisions of "In-place VM disk expand"
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Latest revision as of 13:34, 21 December 2015
Contents
Feature[edit]
prl_disk_tool resize --resize_partition /in-place VM disk expand
Description[edit]
the prl_disk_tool utility now can expand VM disks in-place.
prl_disk_tool resize
worked in-place even before
prl_disk_tool resize --resize_partition
now expands disk, last partition (in case of logical paritition, the extended container as well) and its filesystem.
As before, you will need:
libguestfs-winsupport
for last ntfs partitionlibguestfs-xfs
for last xfs partitionbtrfs-progs
for last btrfs partition
The approximate algorithm is as following (for GPT):
- part-list -> (start, end); blockdev-getsize64 -> diskEnd; store partition attrs
- create overlay image of size newSize on top of current
- debug sh 'sgdisk -e /dev/sdaN' (working on libguestfs API)
- part-del /dev/sda N
- part-add /dev/sda attrs.type start (blockdev-getsize64 - (diskEnd - end))
- restore partition attrs
- stretch filesystem (resize2fs, ntfsresize etc)
- prl_disk_tool merge --external overlay (qemu-img commit)
For MBR, we avoid step (3) and repeat (4)-(5) for extended partition before resizing logical (if needed).
If something goes wrong before (8), we just remove overlay and nothing will change to original image. Overlay is lightweight: for 1GB full disk it used only 6.3Mb of space (I think it's affordable).
Products[edit]
Virtuozzo 7
Packages
- prl-disk-tool >= 7.0.7
- libguestfs >= 1.31.7
- btrfs-progs >= 4.2 (optional)
- libguestfs-winsupport >= 7.2.1 (optional)
- libguestfs-xfs (in dependencies)
- qemu-img >= 1.5.3-86
Testing[edit]
Need to test the following cases:
- resize --resize_partition /works for ext2/ext3/ext4/ntfs/btrfs/xfs/swap last partitions
- it works for GPT partitions, preserving partition attributes
- it works for MBR partitions (primary/extended/logical), preserving partition attributes.
Known issues[edit]
- only listed filesystems are supported
- LVM is not supported (working on it)
- GPT disk GUID is not preserved (it may cause specific OSes to fail - need to check which ones)
- Resizing drops internal snapshots (working on it)
Person responsible for the feature[edit]
Maxim Perevedentsev (mperevedentsev at virtuozzo.com)