I ran a nss /poolverify on my file server that has been having some
connectivity issues, particularly, it would seem, during backup. It
got nearly all the way through, but then ended with this message:

Invalid Free Tree Node

but that's all it gave me. I've looked high and low to try to figure
out what the heck that means, and have found nothing. I don't want to
do a rebuild on the volume until I know whether it is necessary, and
whether or not this is likely to cause it to trash the volume.

Can anyone give me an idea what this means, and what I might want to
consider as my next step?