I run a FreeBSD 9.0 server with ZFS pool version 28 and ZFS version 5.
I had two pools with a log on ssd's two partitions. These pools was created on FreeBSD 8.2 with ZFS pool version 15, and ZFS version 4.
After I upgraded to the new zfs version, I tried to remove the SSD log device from both pools both command was successful (no error message). One of the pools was the log removed, but the other still there, I down the server removed the ssd physically, and hoped it will be forgot by the zpool.
The zpool became degraded as ssd was missing. I tied to remove again. No error message, but the log device entry still there. After it, to became the pool online again, I created a file on the root UFS partition and replaced the missing to device to this file. It was successful, the pool again online. However I can't remove the log device from the pool.

Where can I have to look for error messages? (in dmesg there is nothing about it, also the zfs remove doesn't have any error message, it's seem like it was successful.