oam/knowledge base/synology dsm.md

Synology DiskStation Manager

Rsync

Requirements:

1. the rsync service is enabled under Control Panel > File Services > rsync

2. the user has the right permissions for the shared folder under either

   • Control Panel > Shared Folders > Shared Folder edit window > Permissions, or
   • Control Panel > User & Group > User or Group edit window > Permissions

Examples:

# From a shared folder on a NAS to a local one.
rsync \
  --archive --hard-links \
  --append-verify --partial \
  --progress --verbose \
  --compress --no-motd \
  --exclude "@*" --exclude "#*" \
  "user@nas:/volume1/shared_folder/" \
  "path/to/local/folder/" \
  --delete --dry-run

# Sync all snapshotted data to a folder
find /volume1/@sharesnap/shared_folder \
  -maxdepth 1 -mindepth 1 \
  -type d
| xargs -I {} -n 1 -t \
    rsync \
      -AXahvz --chown=user --info=progress2 \
      --append-verify --partial \
      --no-inc-recursive --no-motd \
      {}/ \
      /volume2/destination/folder/

Snapshots

Use the Snapshot Replication package available in the Package Center for better control and automation.

Gotchas:

1. when the Make snapshot visible option in a shared folder's settings in Snapshot Replication is ticked:

   • the #snapshot folder is created in the shared folder's root directory

   • the default snapshots directory for that shared folder is mounted on it in read only mode:

     /dev/mapper/cachedev_0 on /volume1/Data/#snapshot type btrfs (ro,nodev,relatime,ssd,synoacl,space_cache=v2,auto_reclaim_space,metadata_ratio=50,block_group_cache_tree,subvolid=266,subvol=/@syno/@sharesnap/Data)
     

Deduplicate blocks in a volume

Requirements:

1. docker needs to be installed from the package manager, as it is simpler to run a container than installing duperemove and all its dependencies on the machine
2. the container needs to be run in privileged mode (--privileged) due to its actions on the disk

Gotchas:

1. the container might fail on very large datasets, usually due to Out Of Memory (OOM) issues; to avoid this:

   1. offload the hashes from RAM using a hash file (--hashfile "/volume1/NetBackup/duperemove.tmp")
   2. use smaller datasets where possible, like a shared folder and just one of its snapshots instead of all of them

2. duperemove can dedupe blocks only if acting on folders in a rw mount; when deduplicating snapshots, use their rw mount path /@syno/@sharesnap/shared_folder instead of their ro version /volumeN/shared_folder/#snapshot

Examples:

# small/medium dataset
# 2 folders in a shared folder
sudo docker run --privileged \
  --rm --name duperemove \
  --mount "type=bind,source=/volume1/Data,target=/sharedfolder" \
  michelecereda/duperemove:0.11.2 \
    -Adhr \
    "/sharedfolder/folder1" "/sharedfolder/folder2"

# large dataset
# 1 shared folder and all its snapshots
sudo docker run --privileged \
  --rm --name duperemove \
  --mount "type=bind,source=/volume1,target=/volume1" \
  michelecereda/duperemove:0.11.2 \
    -Adhr \
    --hashfile "/volume1/NetBackup/duperemove.tmp" \
    "/volume1/Data" "/volume1/@sharesnap/Data"

Sources

• Configuring deduplication block on the Synology