我有一台带有 ZFS 的备份服务器（Ubuntu 16.04；32GB RAM，4x6TB HDD，raidz2）。最近我发现可用空间存在问题。
# zpool list -v
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
pool 21.6T 19.9T 1.76T - 62% 91% 2.30x ONLINE -
raidz2 21.6T 19.9T 1.76T - 62% 91%
sda5 - - - - - -
sdb5 - - - - - -
sdc5 - - - - - -
sdd5 - - - - - -
看起来几乎所有空间都已分配。我不知道是什么占用了它。看看卷大小：
# zfs list -o space
NAME AVAIL USED USEDSNAP USEDDS USEDREFRESERV USEDCHILD
pool 425G 13.4T 0 140K 0 13.4T
pool/backup 425G 742G 0 140K 0 742G
pool/backup/avol 425G 69.0G 0 198K 0 69.0G
pool/backup/avol/old_dumps 425G 69.0G 0 69.0G 0 0
pool/backup/nnn 425G 517G 0 163K 0 517G
pool/backup/nnn/cdvol 425G 5.00G 0 5.00G 0 0
pool/backup/nnn/himvol 425G 98.3G 0 98.3G 0 0
pool/backup/nnn/irvol 425G 33.8G 0 140K 0 33.8G
pool/backup/nnn/irvol/smavol 425G 33.8G 0 33.8G 0 0
pool/backup/nnn/menvol 425G 931M 0 931M 0 0
pool/backup/nnn/nevvol 425G 77.9G 0 77.9G 0 0
pool/backup/nnn/scovol 425G 27.4G 0 27.4G 0 0
pool/backup/nnn/vm 425G 274G 0 16.5M 0 274G
pool/backup/nnn/vm/123 425G 1.47G 0 1.47G 0 0
pool/backup/nnn/vm/124 425G 9.23G 0 9.23G 0 0
pool/backup/nnn/vm/125 425G 13.5G 0 13.5G 0 0
pool/backup/nnn/vm/126 425G 10.5G 0 10.5G 0 0
pool/backup/nnn/vm/128 425G 16.9G 0 16.9G 0 0
pool/backup/nnn/vm/130 425G 8.96G 0 8.96G 0 0
pool/backup/nnn/vm/131 425G 147G 0 147G 0 0
pool/backup/nnn/vm/132 425G 11.3G 0 11.3G 0 0
pool/backup/nnn/vm/135 425G 39.7G 0 39.7G 0 0
pool/backup/nnn/vm/136 425G 16.0G 0 16.0G 0 0
pool/backup/old 425G 50.5G 0 140K 0 50.5G
pool/backup/old/himvol 425G 50.5G 0 50.5G 0 0
pool/backup/telvol 425G 105G 0 105G 0 0
pool/backup2 425G 2.74T 0 140K 0 2.74T
pool/backup2/nnn 425G 2.74T 0 140K 0 2.74T
pool/backup2/nnn/vm 425G 2.74T 0 151K 0 2.74T
pool/backup2/nnn/vm/101 425G 28.0G 0 28.0G 0 0
pool/backup2/nnn/vm/103 425G 38.0G 0 38.0G 0 0
pool/backup2/nnn/vm/104 425G 333G 0 333G 0 0
pool/backup2/nnn/vm/105 425G 526M 0 526M 0 0
pool/backup2/nnn/vm/106 425G 17.1G 0 17.1G 0 0
pool/backup2/nnn/vm/107 425G 17.0G 0 17.0G 0 0
pool/backup2/nnn/vm/109 425G 235G 0 235G 0 0
pool/backup2/nnn/vm/110 425G 321G 0 321G 0 0
pool/backup2/nnn/vm/111 425G 1.11G 0 1.11G 0 0
pool/backup2/nnn/vm/112 425G 73.6G 0 73.6G 0 0
pool/backup2/nnn/vm/114 425G 1.27T 0 1.27T 0 0
pool/backup2/nnn/vm/116 425G 1.31G 0 1.31G 0 0
pool/backup2/nnn/vm/117 425G 19.9G 0 19.9G 0 0
pool/backup2/nnn/vm/119 425G 7.15G 0 7.15G 0 0
pool/backup2/nnn/vm/121 425G 178G 0 178G 0 0
pool/backup2/nnn/vm/122 425G 237G 0 237G 0 0
最近我关闭了重复数据删除功能并复制了所有卷（zfs send | zfs accept; zfs destroy）以删除重复数据删除的数据，但它仍然存在：
# zpool status -D
pool: pool
state: ONLINE
scan: scrub in progress since Wed Jul 12 11:23:27 2017
1 scanned out of 19.9T at 1/s, (scan is slow, no estimated time)
0 repaired, 0.00% done
config:
NAME STATE READ WRITE CKSUM
pool ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
sda5 ONLINE 0 0 0
sdb5 ONLINE 0 0 0
sdc5 ONLINE 0 0 0
sdd5 ONLINE 0 0 0
errors: No known data errors
dedup: DDT entries 41434395, size 978 on disk, 217 in core
bucket allocated referenced
______ ______________________________ ______________________________
refcnt blocks LSIZE PSIZE DSIZE blocks LSIZE PSIZE DSIZE
------ ------ ----- ----- ----- ------ ----- ----- -----
1 25.3M 2.41T 1.95T 1.99T 25.3M 2.41T 1.95T 1.99T
2 5.00M 469G 340G 347G 11.2M 1.03T 762G 779G
4 7.37M 549G 438G 451G 36.9M 2.69T 2.14T 2.21T
8 1.41M 124G 80.7G 83.5G 14.6M 1.26T 833G 862G
16 281K 16.8G 10.7G 11.5G 5.72M 337G 219G 235G
32 73.7K 4.57G 3.79G 3.96G 3.14M 198G 167G 174G
64 40.5K 2.58G 2.32G 2.41G 3.25M 215G 195G 202G
128 8.49K 358M 272M 298M 1.38M 60.2G 45.7G 50.0G
256 3.22K 201M 171M 180M 1.10M 69.8G 59.7G 62.7G
512 1.46K 56.1M 52.2M 56.9M 1.20M 41.1G 38.1G 42.1G
1K 372 12.5M 10.4M 11.7M 501K 19.5G 16.3G 18.0G
2K 169 7.41M 6.14M 6.78M 468K 20.3G 17.0G 18.8G
4K 64 3.40M 2.69M 2.85M 358K 19.1G 15.0G 15.9G
8K 14 316K 172K 238K 151K 3.37G 1.82G 2.52G
16K 10 35.5K 31.5K 75.6K 206K 738M 667M 1.54G
32K 4 102K 85.5K 105K 185K 4.71G 3.93G 4.79G
256K 2 1K 1K 11.6K 704K 352M 352M 4.00G
Total 39.5M 3.55T 2.81T 2.87T 106M 8.36T 6.42T 6.61T
也许这就是原因？ 有没有办法检查哪些数据在使用重复数据删除并将其删除？ 还有什么会消耗磁盘空间？
zpool scrub 有点奇怪。我 6 小时前（CEST 时区）启动了它，目前状态为：
scan: scrub in progress since Wed Jul 12 15:48:20 2017
1 scanned out of 20.0T at 1/s, (scan is slow, no estimated time)
0 repaired, 0.00% done
服务器负载很大（正常运行时间从 2 增加到 80），iostat 显示磁盘利用率为 100％，但没有任何进程正在运行（ssh 服务器除外）。
更新：今天我有近 1TB 的可用空间。服务器上没有执行任何操作，也许 zfs 需要一些时间来清理旧数据？
已解决：问题已解决。重复数据删除表现在为空，有 6.75 TB 的可用空间！zfs 花了大约 6 天时间才清理干净。
答案1
运行python脚本检测并删除重复的数据文件：
http://code.activestate.com/recipes/362459-dupinator-detect-and-delete-duplicate-files/