need help with ZFS

[Mikhail (Plus Plus)]

Olivier Smedts wrote:
> 2009/8/24 Matt Simerson <matt at corp.spry.com>:
>> On Aug 24, 2009, at 6:05 AM, Mikhail (Plus Plus) wrote:
>>
>>> Panagiotis Christias wrote:
>>>> I would suggest you try FreeBSD 8.0 that includes the latest version of
>>>> ZFS (version 13), which fixed several problems present in 7.x. Then,
>>>> check for crash dumps (see dumpon(8)), collect any available info and
>>>> sent it to the list.
>> I second this recommendation. The ZFS code in 8.0 is considerably more
>> stable than what's currently in 7.2-STABLE.
>>
>>> Does that mean I will have to format my current zpool in order to
>>> "upgrade" to ZFS v13? And if it is true then another problem is that I have
>>> to backup current data somewhere before I'll be able to format zpool to new
>>> version, but I cannot do this because server simply crashes every time I try
>>> to copy that much of data to another hdd.
>> Not at all. Simply install 8.0 and do a zpool upgrade.
> 
> And don't forget to zfs upgrade after the zpool upgrade !

Thanks everyone who responded.
I've followed the advice and installed FreeBSD-8.0BETA3-amd64 on that 
server. OS resides on dedicated SATA HD, so all other hard drives left 
untouched.
Now I cannot see zfs pool online.
I've enabled ZFS in /etc/rc.conf, reboot the server, but I cannot see my 
zpool.

zen# zpool list
no pools available
zen#

I remember ZFS relies on hostid, and I've checked my current hostid is 
identical to the one that I had when I ran 7.2.

What do I do now to see my zpool again?

Thanks,
Mikhail.