zdb -S でわかるらしいのでやってみた。
% zpool status -v
pool: tank
state: ONLINE
status: The pool is formatted using an older on-disk format. The pool can
still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'. Once this is done, the
pool will no longer be accessible on older software versions.
scan: scrub repaired 0 in 6h35m with 0 errors on Thu May 5 10:04:39 2011
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
ada1s2 ONLINE 0 0 0
ada2s2 ONLINE 0 0 0
ada3s2 ONLINE 0 0 0
logs
label/zil ONLINE 0 0 0
errors: No known data errors
% zpool iostat
capacity operations bandwidth
pool alloc free read write read write
---------- ----- ----- ----- ----- ----- -----
tank 1.06T 898G 15 24 120K 299K
% zpool iostat -v
capacity operations bandwidth
pool alloc free read write read write
----------- ----- ----- ----- ----- ----- -----
tank 1.06T 898G 15 24 120K 299K
raidz1 1.06T 898G 15 24 120K 251K
ada1s2 - - 4 11 163K 127K
ada2s2 - - 4 11 161K 127K
ada3s2 - - 4 11 161K 127K
label/zil 204K 1.95G 0 0 14 48.5K
----------- ----- ----- ----- ----- ----- -----
% zdb -S tank
Simulated DDT histogram:
bucket allocated referenced
______ ______________________________ ______________________________
refcnt blocks LSIZE PSIZE DSIZE blocks LSIZE PSIZE DSIZE
------ ------ ----- ----- ----- ------ ----- ----- -----
1 336K 9.61G 9.61G 9.67G 336K 9.61G 9.61G 9.67G
2 6.02K 215M 215M 216M 12.7K 442M 442M 444M
4 592 9.52M 9.52M 9.64M 2.78K 43.3M 43.3M 43.9M
8 223 1.77M 1.77M 1.83M 2.13K 18.2M 18.2M 18.7M
16 19 39K 39K 42.6K 408 854K 854K 931K
32 7 35K 35K 36.6K 315 1.96M 1.96M 2.03M
64 5 130K 130K 131K 503 14.9M 14.9M 15.0M
128 1 512 512 682 178 89K 89K 119K
256 3 1.50K 1.50K 2.00K 1.17K 598K 598K 797K
512 3 1.50K 1.50K 2.00K 2.16K 1.08M 1.08M 1.44M
1K 1 512 512 682 1.20K 612K 612K 816K
Total 343K 9.83G 9.83G 9.89G 359K 10.1G 10.1G 10.2G
dedup = 1.03, compress = 1.00, copies = 1.01, dedup * compress / copies = 1.02
%
表の意味はよくわからんが、最後の1行だけみると全く効果なしのようだ。
