Setup

test done on Synology DS-220+ 7.2.2 (geminilake)

SHR 2x18TB HDD (RAID1)


how to get jdupes on Synology

root@storage:~# grep -e product_version -e platform_name  /etc/synoinfo.conf
platform_name="geminilake"
last_show_upgrade_mask_in_login_product_version="7.2.2"

https://synocommunity.com/package/synocli-file

https://packages.synocommunity.com/synocli-file/27/synocli-file.v27.f42661%5Bapollolake-avoton-braswell-broadwell-broadwellnk-broadwellnkv2-broadwellntbap-bromolow-cedarview-denverton-epyc7002-geminilake-grantley-kvmx64-purley-r1000-v1000%5D.spk

State before deduplication


root@storage:~# df -h /volume1
Filesystem      Size  Used Avail Use% Mounted on
/dev/vg1000/lv   16T   12T  4.1T  75% /volume1

root@storage:~# mount |grep /volume1
/dev/mapper/vg1000-lv on /volume1 type btrfs (rw,nodev,relatime,ssd,synoacl,nospace_cache,auto_reclaim_space,metadata_ratio=50,syno_allocator,subvolid=257,subvol=/@syno)

execute deduplicate of backup folder


root@storage:~# jdupes --one-file-system --dedupe --recurse --size /volume1/backup/
Scanning: 761995 files, 109877 items (in 2 specified)
Progress [138877/761995, 32742 pairs matched] 18%
...

on backup folder jdupes processing take 7.5h

results is +0.3TB

root@storage:~# df -h /volume1
Filesystem        Size  Used Avail Use% Mounted on
/dev/vg1000/lv     16T   12T  4.4T  73% /volume1


root@storage:~# btrfs filesystem du --summarize --human-readable /volume1/backup/
     Total   Exclusive  Set shared  Filename
   1.58TiB   995.21GiB   293.23GiB  /volume1/backup/

deduplicate shared folder

root@storage:~# jdupes --one-file-system --dedupe --recurse --size /volume1/backup/

took about 55 hours

add about 2.6TB of free space

root@storage:~# df -h /volume1
Filesystem      Size  Used Avail Use% Mounted on
/dev/vg1000/lv   16T  8.7T  7.1T  56% /volume1

So total free space gain is 3TB (from 12TB used) and 62 hours of duduplication run