Known Issues

This section provides a short list of known issues.

Mount Path Limit

There is a known mountpoint path length limitation issue on FreeBSD. Path length has an historical 88 character limit.

This issue does not affect iocage jails from functioning properly, but can present challenges when diving into ZFS snapshots, like cd into .zfs/snapshots, tar, etc.

ZFS snapshot creation and rollback is not affected.

To work around this issue, iocage allows the user to assign and use a unique NAME for the jail. Alternately, using the [-s | –short] flag at jail creation tells iocage to assign a shortened UUID to the jail.


VNET/VIMAGE can cause unexpected system crashes when VNET enabled jails are destroyed. In other words, when the jail process is killed, removed, or stopped.

As a workaround, iocage allows a soft restart without destroying the jail. iocage restart -s [UUID | NAME] executes a soft restart of the jail.


# iocage restart -s examplejail

FreeBSD 10.1-RELEASE is stable enough to run with VNET and soft restarts. There are production machines with iocage and VNET jails running well over 100 days of uptime running both PF and IPFW.


As recent as FreeBSD 10.1-RELEASE-p10, there are some interesting interactions between VNET/VIMAGE and the ALTernate Queueing (ALTQ) system used by PF and other routing software. When compiling a kernel, be sure these lines are not in the kernconf file (unless disabling VNET):

options     ALTQ
options     ALTQ_CBQ
options     ALTQ_RED
options     ALTQ_RIO
options     ALTQ_HFSC
options     ALTQ_CDNR
options     ALTQ_PRIQ

Otherwise, when starting a jail with VNET support enabled, the host system is likely to crash. Read a more about this issue from a 2014 mailing list post.

IPv6 host bind failures

In some cases, a jail with an ip6 address may take too long adding the address to the interface. Services defined to bind specifically to the address may then fail. If this happens, add this to sysctl.conf to disable DAD (duplicate address detection) probe packets:

# disable duplicated address detection probe packets for jails

Adding these lines permanently disables DAD. To set this for ONLY the current system boot, type sysctl net.inet6.ip6.dad_count=0 in a command line interface (CLI). More information about this issue is available from a 2013 mailing list post.