some (random) jails are not started after reboot

[Miroslav Lachman]

Hi,

we have a few machines running jails as "vps". All jails are maintained 
by me and have normal setup with one IPv4. We are running usual web 
things in jails like Apache, PHP, Python, MySQL.

I noticed that some jails are not started after reboot on one machine. 
(after security update to 10.3-RELEASE-p6 in the summer)
I updated our machines last night to 10.3-RELEASE-p9 and one jail on the 
same machine did not start.
Console log of this jail does not contain any startup messages. The last 
record are from previous start.
I can start the jail manually without any problem. No errors.

Only one machine has this problem. Problem started a few months back. 
(The machine was started as some old 8.x install and is continually 
upgraded to the latest 10.3)
Base system is on UFS, jails are on ZFS if it matter.

This is production machine so I can't play with it too much. But does 
anybody else seen it too?
How can I debug it on next reboot?

Miroslav Lachman