Unable to upgrade ZFS pool to feature flags, SPA version 5000, on stable/9 @ r243825

[Trond Endrestøl]

Hi,

I installed FreeBSD/amd64 9.1-RELEASE yesterday.
I chose to do a manual installation due to the use of ZFS.
I checked out stable/9 and recompiled both world and GENERIC kernel.
Said kernel and world was installed without any problems.
System is still up & running, with uname -a revealing r243825.

I then decided to upgrade the root pool to feature flags, SPA version 
5000, and was not so lucky.

# zpool upgrade -a
This system supports ZFS pool feature flags.

cannot upgrade 'zroot': invalid argument for this pool operation

Even the command:

zpool upgrade zroot

gives the same diagnostic as above.

This isn't a critical system at all, but I guess everyone else will 
run into this snag when attempting to upgrade their ZFS pools.

Any clues?

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