[zfs-discuss] dedupe question

[Dennis Clarke]

>
> You can get more dedup information by running 'zdb -DD zp_dd'. This
> should show you how we break things down. Add more 'D' options and get
> even more detail.
>
> - George

OKay .. thank you. Looks like I have piles of numbers here :

# zdb -DDD zp_dd
DDT-sha256-zap-duplicate: 37317 entries, size 342 on disk, 210 in core

bucket              allocated                       referenced
______   ______________________________   ______________________________
refcnt   blocks   LSIZE   PSIZE   DSIZE   blocks   LSIZE   PSIZE   DSIZE
------   ------   -----   -----   -----   ------   -----   -----   -----
     2    18.4K    763M    355M    355M    37.9K   1.52G    727M    727M
     4    18.0K   1.16G   1.15G   1.15G    72.4K   4.67G   4.61G   4.61G
     8       70   1.47M    849K    849K      657   12.0M   6.78M   6.78M
    16       27   39.5K   31.5K   31.5K      535    747K    598K    598K
    32        6      4K      4K      4K      276    180K    180K    180K
    64        4   9.00K   6.50K   6.50K      340    680K    481K    481K
   128        1      2K   1.50K   1.50K      170    340K    255K    255K
   256        1      1K      1K      1K      313    313K    313K    313K
   512        1     512     512     512      522    261K    261K    261K
 Total    36.4K   1.91G   1.50G   1.50G     113K   6.21G   5.33G   5.33G

DDT-sha256-zap-unique: 154826 entries, size 335 on disk, 196 in core

bucket              allocated                       referenced
______   ______________________________   ______________________________
refcnt   blocks   LSIZE   PSIZE   DSIZE   blocks   LSIZE   PSIZE   DSIZE
------   ------   -----   -----   -----   ------   -----   -----   -----
     1     151K   5.61G   2.52G   2.52G     151K   5.61G   2.52G   2.52G
 Total     151K   5.61G   2.52G   2.52G     151K   5.61G   2.52G   2.52G


DDT histogram (aggregated over all DDTs):

bucket              allocated                       referenced
______   ______________________________   ______________________________
refcnt   blocks   LSIZE   PSIZE   DSIZE   blocks   LSIZE   PSIZE   DSIZE
------   ------   -----   -----   -----   ------   -----   -----   -----
     1     151K   5.61G   2.52G   2.52G     151K   5.61G   2.52G   2.52G
     2    18.4K    763M    355M    355M    37.9K   1.52G    727M    727M
     4    18.0K   1.16G   1.15G   1.15G    72.4K   4.67G   4.61G   4.61G
     8       70   1.47M    849K    849K      657   12.0M   6.78M   6.78M
    16       27   39.5K   31.5K   31.5K      535    747K    598K    598K
    32        6      4K      4K      4K      276    180K    180K    180K
    64        4   9.00K   6.50K   6.50K      340    680K    481K    481K
   128        1      2K   1.50K   1.50K      170    340K    255K    255K
   256        1      1K      1K      1K      313    313K    313K    313K
   512        1     512     512     512      522    261K    261K    261K
 Total     188K   7.52G   4.01G   4.01G     264K   11.8G   7.85G   7.85G

dedup = 1.96, compress = 1.51, copies = 1.00, dedup * compress / copies =
2.95

#

I have no idea what any of that means, yet :-)

-- 
Dennis Clarke
dclarke at opensolaris.ca  <- Email related to the open source Solaris
dclarke at blastwave.org   <- Email related to open source for Solaris