[Users] Ploop conversion (Error in tune_fs - can't set reserved blocks)

[Corrado Fiore]

Dear All,

today, during the conversion of a container to Ploop storage, I encountered some issues.

My host is a CentOS box (2.6.32-042stab081.3) with the latest ploop and ploop-lib installed (1.12-1).  When I issued the usual command `vzctl convert NNN`, the conversion process started but towards the end it printed:

Error in tune_fs (fsutils.c:180): Can't set reserved blocks to 668415: Inappropriate ioctl for device

I could start the CT and enter it.  However, df -h was showing weird values (0 bytes available):

# df -h
Filesystem         Size  Used Avail Use% Mounted on
/dev/ploop44599p1   52G  1.4G     0 100% /
none               512M  4.0K  512M   1% /dev
none               512M     0  512M   0% /dev/shm

In fact, applications like Nginx believed that there was no space available and refused to write logs for example.  But I was able to create a new file with the Nano editor.

I tried the following to rectify the situation, without success:

1)  `vzctl set NNN --disk MMMG --save`, with various values of MMM

2)  deleting the INODES settings from the CT conf file and restarting

3)  `tune2fs -m 5 /dev/ploop53231p1`

In the end, I decided to just create a new container on a different host machine and transfer all application data from the latest backup (which I did minutes before issuing the conversion).

Can you give me any clues about what happened?

Thanks,
Corrado Fiore