If I have 2 raidz''s, 5x400G and a later added 5x1T, should I expect that streaming writes would go primarily to only 1 of the raidz sets? Or is this some side effect of my non-ideal hardware setup? I thought that adding additional capacity to a pool automatically would then balance writes to both raidz''s, but does not seem to fit what I''ve seen empirically. What am I missing? Note that the following is a snapshot of time in the middle of a large streaming write, not the initial output from zpool iostat. Thomas zpool iostat -v tank 1 capacity operations bandwidth pool used avail read write read write ---------- ----- ----- ----- ----- ----- ----- tank 1.72T 4.65T 9 379 156K 30.7M raidz1 1.66T 166G 9 329 156K 30.5M c0t0d0 - - 4 152 282K 7.64M c0t4d0 - - 4 155 282K 7.64M c1t0d0 - - 2 153 188K 7.64M c1t4d0 - - 3 161 220K 7.64M c1t1d0 - - 1 158 94.1K 7.64M raidz1 65.2G 4.48T 0 50 0 158K c0t5d0 - - 0 72 0 82.4K c1t2d0 - - 0 69 0 80.4K c1t6d0 - - 0 72 0 83.3K c0t2d0 - - 0 0 0 0 c0t6d0 - - 0 73 0 87.3K ---------- ----- ----- ----- ----- ----- -----