Partition size rounding incorrect inside LVM

[Arjen Lentz]

When using the manual partition tool in Ubuntu (Hardy) server installer, to for instance set up RAID1 then LVM, then partitions...
The partition create option suggests the maximum available space on disk in MBs.
I then reduce that for the last partition in the LVM group, so there's some free space for snapshots.
The partition rounds it up to the next extent, and ends up at more than the available free space? Very odd.
Try it by reducing the last suggested partition size with say 10GB (10000MB) and see what's reported.

Suggestions:
a) the partitioner could actually suggest leaving some freespace in an LVM group, otherwise snapshots are impossible.
b) if I lower the size suggested, the upward rounding (for extent size) cannot possibly exceed the originally suggested size ;-)

[Phillip Susi (psusi)]

Logical volumes are allocated in extents, so their size must be rounded.

[Arjen Lentz (arjen-lentz)]

Phillip, what you say is absolutely correct, but actually confirms rather than invalidates the original bug report.

Please reconsider the original report and the suggestions of what can be done to make the code behave correctly.