adding drive to raidz1

[Randy Bush]

>> on the two bootables
>>    s1 is a small gmirroed boot
>>    s2 is a non-mirrored swap
>>    s3 is pool
> Just out of sheer curiosity, are all the slices and devices in the raidz 
> the same size?

no they were not.  and now it is not a raidz, but rather

        NAME        STATE     READ WRITE CKSUM
        tank        ONLINE       0     0     0
          mirror    ONLINE       0     0     0
            ad4s3   ONLINE       0     0     0
            ad5s3   ONLINE       0     0     0
          mirror    ONLINE       0     0     0
            ad6s1   ONLINE       0     0     0
            ad7s1   ONLINE       0     0     0

randy