USB to FreeNAS Disk Space Discrepancy (Compression?)

[TS_TECH]

Hello,

I have a USB drive with around 1.7TB of files on it. I copied everything to my FreeNAS system and the resulting Disk utilization was 512GB.

I ran "zfs get all NetStorage" and it reported the compression ratio as 1.32x. Can someone please help me understand how these numbers add up?

1.7TB to 0.512TB seems closer to a 3:1 ratio. What am I missing?

Also, to ensure my initial copy did not miss any files, I ran rsync on the two folders.

Thanks.
TS

 

[cyberjock]

I can't explain your problem because you didn't include all relevant info. To be honest, that's the indicator you don't understand all of the relationships of things. ;)

In particular, I'd recommend you read up on compression, snapshots, datasets and pools. There's a bunch of other numbers that you didn't include (presumbly because you don't even realize they matter), but once you understand all of the relationships you'll see it's not as easy as you think and you can't compare two numbers and have your answer. ;)

 

[TS_TECH]

cyberjock...

I appreciate the RTFM flavored response. Please consider the following information:

I am dealing with only one pool (named NetStorage), and only one dataset (named NetStorage). I do not have any snapshot configurations implemented. Also, this is largely a default configuration including the default compression settings. I am trying to make sense of the "compressratio 1.32x" reported when running "zfs get all NetStorage"

Code:

NAME        PROPERTY              VALUE                  SOURCE
NetStorage  type                  filesystem             -
NetStorage  creation              Fri Nov 21  3:30 2014  -
NetStorage  used                  515G                   -
NetStorage  available             1.46T                  -
NetStorage  referenced            515G                   -
NetStorage  compressratio         1.32x                  -
NetStorage  mounted               yes                    -
NetStorage  quota                 none                   default
NetStorage  reservation           none                   default
NetStorage  recordsize            128K                   default
NetStorage  mountpoint            /mnt/NetStorage        default
NetStorage  sharenfs              off                    default
NetStorage  checksum              on                     default
NetStorage  compression           lz4                    local
NetStorage  atime                 on                     default
NetStorage  devices               on                     default
NetStorage  exec                  on                     default
NetStorage  setuid                on                     default
NetStorage  readonly              off                    default
NetStorage  jailed                off                    default
NetStorage  snapdir               hidden                 default
NetStorage  aclmode               passthrough            local
NetStorage  aclinherit            passthrough            local
NetStorage  canmount              on                     default
NetStorage  xattr                 off                    temporary
NetStorage  copies                1                      default
NetStorage  version               5                      -
NetStorage  utf8only              off                    -
NetStorage  normalization         none                   -
NetStorage  casesensitivity       sensitive              -
NetStorage  vscan                 off                    default
NetStorage  nbmand                off                    default
NetStorage  sharesmb              off                    default
NetStorage  refquota              none                   default
NetStorage  refreservation        none                   default
NetStorage  primarycache          all                    default
NetStorage  secondarycache        all                    default
NetStorage  usedbysnapshots       0                      -
NetStorage  usedbydataset         515G                   -
NetStorage  usedbychildren        6.76M                  -
NetStorage  usedbyrefreservation  0                      -
NetStorage  logbias               latency                default
NetStorage  dedup                 off                    default
NetStorage  mlslabel                                     -
NetStorage  sync                  standard               default
NetStorage  refcompressratio      1.32x                  -
NetStorage  written               515G                   -
NetStorage  logicalused           671G                   -
NetStorage  logicalreferenced     671G                   -
NetStorage  volmode               default                default

 

[marbus90]

Looking at #49 it tells you that you wrote 671GiB to the dataset. Possible source of trouble?
- rsync f'd up
- volume shadow copies/snapshots
- hidden files