今天早上，我在FreeNAS 9.3机器上发出警告，提示“空间不足”
warning: The capacity for the volume 'SeanVolume' is currently at 85%, while the recommended value is below 80%. 一段时间后运行scrub命令是没有用的。
我使用SSHlogin到FreeNAS主机，并获得一些信息：
[root@freenas] ~# zpool list NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT SeanVolume 21.8T 18.6T 3.16T - 38% 85% 1.00x ONLINE /mnt freenas-boot 111G 680M 110G - - 0% 1.00x ONLINE -
它显示它的ALLOC空间只有18.6T的容量，但它仍然有6.7T通过du -sh命令：
[root@freenas] ~# du -sh /mnt/SeanVolume/ 6.7T /mnt/SeanVolume/
附加信息：
[root@freenas] ~# zpool status pool: SeanVolume state: ONLINE scan: scrub repaired 0 in 20h32m with 0 errors on Thu Jul 16 07:48:34 2015 config: NAME STATE READ WRITE CKSUM SeanVolume ONLINE 0 0 0 raidz3-0 ONLINE 0 0 0 gptid/f4986ea8-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f51a05f7-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f595d78e-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f62490d4-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f6a8e41e-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f7266471-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f7f3bf28-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/f8b8fa7b-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 cache gptid/f901ec00-f822-11e4-a7d4-d05099265144 ONLINE 0 0 0 gptid/dfa53351-1baa-11e5-ba0e-d05099265144 ONLINE 0 0 0 errors: No known data errors
df -TH命令的结果：
[root@freenas] ~# df -TH Filesystem Type Size Used Avail Capacity Mounted on freenas-boot/ROOT/default zfs 115G 698M 114G 1% / devfs devfs 1.0k 1.0k 0B 100% /dev tmpfs tmpfs 33M 5.5M 28M 16% /etc tmpfs tmpfs 4.2M 8.2k 4.2M 0% /mnt tmpfs tmpfs 11G 67M 11G 1% /var freenas-boot/grub zfs 114G 8.1M 114G 0% /boot/grub SeanVolume zfs 1.6T 822k 1.6T 0% /mnt/SeanVolume SeanVolume/CandyDataset zfs 1.6T 299k 1.6T 0% /mnt/SeanVolume/CandyDataset SeanVolume/CandyDataset/Applications zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/CandyDataset/Applications SeanVolume/CandyDataset/Documents zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/CandyDataset/Documents SeanVolume/CandyDataset/Downloads zfs 2.9T 1.3T 1.6T 46% /mnt/SeanVolume/CandyDataset/Downloads SeanVolume/CandyDataset/Music zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/CandyDataset/Music SeanVolume/CandyDataset/Pictures zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/CandyDataset/Pictures SeanVolume/CandyDataset/Temporary zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/CandyDataset/Temporary SeanVolume/CandyDataset/Videos zfs 1.8T 221G 1.6T 12% /mnt/SeanVolume/CandyDataset/Videos SeanVolume/PublicDataset zfs 1.6T 243k 1.6T 0% /mnt/SeanVolume/PublicDataset SeanVolume/PublicDataset/Applications zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Applications SeanVolume/PublicDataset/Documents zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Documents SeanVolume/PublicDataset/Downloads zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Downloads SeanVolume/PublicDataset/Music zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Music SeanVolume/PublicDataset/Pictures zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Pictures SeanVolume/PublicDataset/Temporary zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Temporary SeanVolume/PublicDataset/Videos zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/PublicDataset/Videos SeanVolume/SeanDataset zfs 3.9T 2.3T 1.6T 60% /mnt/SeanVolume/SeanDataset SeanVolume/SeanDataset/AppData zfs 1.6T 224k 1.6T 0% /mnt/SeanVolume/SeanDataset/AppData SeanVolume/SeanDataset/Applications zfs 1.6T 261k 1.6T 0% /mnt/SeanVolume/SeanDataset/Applications SeanVolume/SeanDataset/Documents zfs 3.0T 1.5T 1.6T 48% /mnt/SeanVolume/SeanDataset/Documents SeanVolume/SeanDataset/Downloads zfs 2.2T 647G 1.6T 29% /mnt/SeanVolume/SeanDataset/Downloads SeanVolume/SeanDataset/Music zfs 1.6T 411k 1.6T 0% /mnt/SeanVolume/SeanDataset/Music SeanVolume/SeanDataset/Pictures zfs 1.6T 2.2M 1.6T 0% /mnt/SeanVolume/SeanDataset/Pictures SeanVolume/SeanDataset/Saved Games zfs 1.6T 243k 1.6T 0% /mnt/SeanVolume/SeanDataset/Saved Games SeanVolume/SeanDataset/Temporary zfs 1.6T 533k 1.6T 0% /mnt/SeanVolume/SeanDataset/Temporary SeanVolume/SeanDataset/Videos zfs 2.4T 850G 1.6T 35% /mnt/SeanVolume/SeanDataset/Videos SeanVolume/jails zfs 1.6T 710M 1.6T 0% /mnt/SeanVolume/jails SeanVolume/jails/.warden-template-pluginjail zfs 1.6T 619M 1.6T 0% /mnt/SeanVolume/jails/.warden-template-pluginjail SeanVolume/jails/.warden-template-pluginjail-9.3 zfs 1.6T 619M 1.6T 0% /mnt/SeanVolume/jails/.warden-template-pluginjail-9.3 SeanVolume/jails/pluginjail zfs 1.6T 660M 1.6T 0% /mnt/SeanVolume/jails/pluginjail SeanVolume/ownCloudDataset zfs 1.8T 259G 1.6T 14% /mnt/SeanVolume/ownCloudDataset SeanVolume/.system zfs 1.6T 3.4M 1.6T 0% /var/db/system SeanVolume/.system/cores zfs 1.6T 1.4M 1.6T 0% /var/db/system/cores SeanVolume/.system/samba4 zfs 1.6T 6M 1.6T 0% /var/db/system/samba4 SeanVolume/.system/syslog-cd1fc29ce94d4a81a24df77359252261 zfs 1.6T 6M 1.6T 0% /var/db/system/syslog-cd1fc29ce94d4a81a24df77359252261 SeanVolume/.system/rrd-cd1fc29ce94d4a81a24df77359252261 zfs 1.6T 224k 1.6T 0% /var/db/system/rrd-cd1fc29ce94d4a81a24df77359252261 devfs devfs 1.0k 1.0k 0B 100% /mnt/SeanVolume/jails/pluginjail/dev procfs procfs 4.1k 4.1k 0B 100% /mnt/SeanVolume/jails/pluginjail/proc SeanVolume/jails/customplugin_2 zfs 1.6T 1.4G 1.6T 0% /mnt/SeanVolume/jails/customplugin_2 SeanVolume/SeanDataset/ISOImage zfs 1.6T 318k 1.6T 0% /mnt/SeanVolume/SeanDataset/ISOImage devfs devfs 1.0k 1.0k 0B 100% /mnt/SeanVolume/jails/customplugin_2/dev procfs procfs 4.1k 4.1k 0B 100% /mnt/SeanVolume/jails/customplugin_2/proc /mnt/SeanVolume/ownCloudDataset nullfs 1.8T 259G 1.6T 14% /mnt/SeanVolume/jails/customplugin_2/media
运行清理状态（Web GUI）：
Scrub status: Completed Errors: 0 Repaired: 0 Date: Thu Jul 16 07:48:34 2015
我可以做些什么来尝试解决这个问题（除了重启，因为它在线运行ownCloud插件）？
PS：2015/07/17加了：
[root@freenas] ~# zfs list NAME USED AVAIL REFER MOUNTPOINT SeanVolume 10.7T 1.34T 803K /mnt/SeanVolume SeanVolume/.system 304M 1.34T 3.21M legacy SeanVolume/.system/cores 5.53M 1.34T 1.32M legacy SeanVolume/.system/rrd-cd1fc29ce94d4a81a24df77359252261 219K 1.34T 219K legacy SeanVolume/.system/samba4 218M 1.34T 5.59M legacy SeanVolume/.system/syslog-cd1fc29ce94d4a81a24df77359252261 61.4M 1.34T 5.62M legacy SeanVolume/CandyDataset 1.42T 1.34T 292K /mnt/SeanVolume/CandyDataset SeanVolume/CandyDataset/Applications 365K 1.34T 219K /mnt/SeanVolume/CandyDataset/Applications SeanVolume/CandyDataset/Documents 365K 1.34T 219K /mnt/SeanVolume/CandyDataset/Documents SeanVolume/CandyDataset/Downloads 1.22T 1.34T 1.22T /mnt/SeanVolume/CandyDataset/Downloads SeanVolume/CandyDataset/Music 365K 1.34T 219K /mnt/SeanVolume/CandyDataset/Music SeanVolume/CandyDataset/Pictures 365K 1.34T 219K /mnt/SeanVolume/CandyDataset/Pictures SeanVolume/CandyDataset/Temporary 365K 1.34T 219K /mnt/SeanVolume/CandyDataset/Temporary SeanVolume/CandyDataset/Videos 206G 1.34T 206G /mnt/SeanVolume/CandyDataset/Videos SeanVolume/PublicDataset 3.03M 1.34T 237K /mnt/SeanVolume/PublicDataset SeanVolume/PublicDataset/Applications 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Applications SeanVolume/PublicDataset/Documents 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Documents SeanVolume/PublicDataset/Downloads 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Downloads SeanVolume/PublicDataset/Music 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Music SeanVolume/PublicDataset/Pictures 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Pictures SeanVolume/PublicDataset/Temporary 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Temporary SeanVolume/PublicDataset/Videos 365K 1.34T 219K /mnt/SeanVolume/PublicDataset/Videos SeanVolume/SeanDataset 8.04T 1.34T 2.14T /mnt/SeanVolume/SeanDataset SeanVolume/SeanDataset/AppData 2.64M 1.34T 219K /mnt/SeanVolume/SeanDataset/AppData SeanVolume/SeanDataset/Applications 178G 1.34T 256K /mnt/SeanVolume/SeanDataset/Applications SeanVolume/SeanDataset/Documents 2.58T 1.34T 1.33T /mnt/SeanVolume/SeanDataset/Documents SeanVolume/SeanDataset/Downloads 1.07T 1.34T 661G /mnt/SeanVolume/SeanDataset/Downloads SeanVolume/SeanDataset/ISOImage 103G 1.34T 310K /mnt/SeanVolume/SeanDataset/ISOImage SeanVolume/SeanDataset/Music 51.7G 1.34T 402K /mnt/SeanVolume/SeanDataset/Music SeanVolume/SeanDataset/Pictures 131G 1.34T 2.08M /mnt/SeanVolume/SeanDataset/Pictures SeanVolume/SeanDataset/Saved Games 75.7G 1.34T 237K /mnt/SeanVolume/SeanDataset/Saved Games SeanVolume/SeanDataset/Temporary 9.63G 1.34T 520K /mnt/SeanVolume/SeanDataset/Temporary SeanVolume/SeanDataset/Videos 846G 1.34T 792G /mnt/SeanVolume/SeanDataset/Videos SeanVolume/jails 3.80G 1.34T 678M /mnt/SeanVolume/jails SeanVolume/jails/.warden-template-pluginjail 6.33M 1.34T 591M /mnt/SeanVolume/jails/.warden-template-pluginjail SeanVolume/jails/.warden-template-pluginjail-9.3 597M 1.34T 591M /mnt/SeanVolume/jails/.warden-template-pluginjail-9.3 SeanVolume/jails/customplugin_2 1.17G 1.34T 1.27G /mnt/SeanVolume/jails/customplugin_2 SeanVolume/jails/pluginjail 1.28G 1.34T 630M /mnt/SeanVolume/jails/pluginjail SeanVolume/ownCloudDataset 1.21T 1.34T 255G /mnt/SeanVolume/ownCloudDataset freenas-boot 680M 107G 144K none freenas-boot/ROOT 670M 107G 144K none freenas-boot/ROOT/Initial-Install 8K 107G 659M legacy freenas-boot/ROOT/default 670M 107G 665M legacy freenas-boot/grub 7.76M 107G 7.76M legacy
2015/07/17已添加：
在使用zfs list -t snapshot命令之后，它显示了许多微小的快照（总共2,534个文件…）。
我正在检查，并删除这些快照文件。
删除后，再次运行df -TH ！
2015/07/20地址：
我删除了许多快照文件后，我得到了一些空间！
但…
FreeNAS 9.3 Web GUI崩溃…
在清除大量快照（大约1500）后，FreeNAS 9.3 Web GUI将显示“发生错误”。 两天后
[root@freenas] /etc/defaults# df -TH Filesystem Type Size Used Avail Capacity Mounted on freenas-boot/ROOT/default zfs 115G 698M 114G 1% / devfs devfs 1.0k 1.0k 0B 100% /dev tmpfs tmpfs 33M 5.5M 28M 16% /etc tmpfs tmpfs 4.2M 8.2k 4.2M 0% /mnt tmpfs tmpfs 11G 67M 11G 1% /var freenas-boot/grub zfs 114G 8.1M 114G 0% /boot/grub SeanVolume zfs 4T 822k 4T 0% /mnt/SeanVolume SeanVolume/CandyDataset zfs 4T 299k 4T 0% /mnt/SeanVolume/CandyDataset SeanVolume/CandyDataset/Downloads zfs 5.3T 1.3T 4T 25% /mnt/SeanVolume/CandyDataset/Downloads SeanVolume/CandyDataset/Videos zfs 4.2T 221G 4T 5% /mnt/SeanVolume/CandyDataset/Videos SeanVolume/PublicDataset zfs 4T 224k 4T 0% /mnt/SeanVolume/PublicDataset SeanVolume/SeanDataset zfs 9.6T 5.6T 4T 59% /mnt/SeanVolume/SeanDataset SeanVolume/jails zfs 4T 710M 4T 0% /mnt/SeanVolume/jails SeanVolume/jails/.warden-template-pluginjail zfs 4T 619M 4T 0% /mnt/SeanVolume/jails/.warden-template-pluginjail SeanVolume/jails/.warden-template-pluginjail-9.3 zfs 4T 619M 4T 0% /mnt/SeanVolume/jails/.warden-template-pluginjail-9.3 SeanVolume/jails/pluginjail zfs 4T 661M 4T 0% /mnt/SeanVolume/jails/pluginjail SeanVolume/ownCloudDataset zfs 4.3T 336G 4T 8% /mnt/SeanVolume/ownCloudDataset SeanVolume/.system zfs 4T 3.4M 4T 0% /var/db/system SeanVolume/.system/cores zfs 4T 1.4M 4T 0% /var/db/system/cores SeanVolume/.system/samba4 zfs 4T 6.1M 4T 0% /var/db/system/samba4 SeanVolume/.system/syslog-cd1fc29ce94d4a81a24df77359252261 zfs 4T 11M 4T 0% /var/db/system/syslog-cd1fc29ce94d4a81a24df77359252261 SeanVolume/.system/rrd-cd1fc29ce94d4a81a24df77359252261 zfs 4T 224k 4T 0% /var/db/system/rrd-cd1fc29ce94d4a81a24df77359252261 devfs devfs 1.0k 1.0k 0B 100% /mnt/SeanVolume/jails/pluginjail/dev procfs procfs 4.1k 4.1k 0B 100% /mnt/SeanVolume/jails/pluginjail/proc SeanVolume/jails/customplugin_2 zfs 4T 1.4G 4T 0% /mnt/SeanVolume/jails/customplugin_2 devfs devfs 1.0k 1.0k 0B 100% /mnt/SeanVolume/jails/customplugin_2/dev procfs procfs 4.1k 4.1k 0B 100% /mnt/SeanVolume/jails/customplugin_2/proc /mnt/SeanVolume/ownCloudDataset nullfs 4.3T 336G 4T 8% /mnt/SeanVolume/jails/customplugin_2/media
我试着总结给出的信息，并给出一些解释（我知道，它是什么意思）：
关于zpool列表输出：
SIZE是所有光盘的大小，包括用于冗余的光盘（所以加上zpool状态的输出，也就是说，您已经将8个3TB驱动器放在一个RAID-Z3configuration中）
ALLOC是已使用的空间，也包括用于冗余的光盘（因为8个光盘中的3个用于冗余，所以至less比实际数据大小高（5 + 3）/ 5 = 1.6倍）
Free是可用空间，也包括用于冗余的光盘（所以可用空间最多为5 /（5 + 3）= 0,625所示的自由空间）
zfs列表命令说，有1,34T可用， zpool列表说，3,16T空闲，减去冗余空间，我期望约1,975T。
我知道，zfs需要一些元数据空间，但是在我的linux系统中，RAID-Z1中有4个2TB的驱动器，差异大约是6％，这里的差别大概是47％，我不能说差异来自哪里。
关于df -Th的输出
df没有findzfs快照，所以不能计算它们，所以使用的空间不是zfs文件系统中使用的空间。 对于zfs文件系统中的分配空间，使用zfs列表
删除快照可能需要一段时间，因为您发现了，似乎是由devise，你可以看看http://nex7.blogspot.de/2013/03/readme1st.html
删除快照后，如果我计算你的df输出，你的池中大约有7,2T的数据，大概有4T，所有的都是11,2T。
如果我把你的完整尺寸（21,8T）减去冗余盘，我预计大约5 /（5 + 3）* 21,8T = 13,6T（相差大约20％）
我认为20％对于zfs所需要的元数据有一点点的影响，但我不能告诉你，它在哪里丢失。 也许你有很多非常小的文件，它们使用的元数据空间比没有那么多的大文件要多。
我很抱歉，但是我并没有深入zfs的内部，我可以告诉你，在哪里获得元数据空间的使用。
您可以再次尝试一个zfs列表 ，并将已使用的空间与您从df获得的已用空间进行比较。 也许它提供了一个提示。
编辑21.07.2015
关于大小：3T驱动器实际上有2.7TB（因为驱动器制造商使用1TB = 1.000.000.000.000字节，其中计算机使用1TiB = 1 * 1024 * 1024 * 1024 * 1024 = 1.099.511.627.776字节。
2,7 * 8驱动器= 21,8T
在正常的RAID系统中，最小的驱动器决定了较大驱动器的可用大小。