Duplicacy currently supports local file storage, SFTP, WebDav and many cloud storage providers.
Local disk
Storage URL:
/path/to/storage (on Linux or Mac OS X)
C:\path\to\storage (on Windows)
SFTP
Storage URL:
sftp://username@server/path/to/storage (path relative to the home directory)
sftp://username@server//path/to/storage (absolute path)
Login methods include password authentication and public key authentication. You can set up SSH agent forwarding which is also supported by Duplicacy.
Public key authentication with signed certificate is also supported. That is, if the ssh private key file is ‘mykey’, Duplicacy will check if the signed certificate can be loaded from the file ‘mykey-cert.pub’.
Note for Synology users
If the SFTP server is a Synology NAS, it is highly recommended to use the absolute path (the one with double slashes) in the storage url. Otherwise, Synology’s customized SFTP server may terminate the connections arbitrarily leading to frequent EOF errors.
Dropbox
Storage URL:
dropbox://path/to/storage
For Duplicacy to access your Dropbox storage, you must provide a refresh token that can be obtained by authorizing Duplicacy to access its app folder inside your Dropbox by following this link. Dropbox will generate the refresh token which you then supply to Duplicacy. The actual storage folder will be the path specified in the storage url relative to the Apps folder.
Amazon S3
Storage URL:
s3://amazon.com/bucket/path/to/storage (default region is us-east-1)
s3://region@amazon.com/bucket/path/to/storage (other regions must be specified)
You’ll need to input an access key and a secret key to access your Amazon S3 storage.
Minio-based S3 compatiable storages are also supported by using the minio or minios backends:
minio://region@host/bucket/path/to/storage (without TLS)
minios://region@host/bucket/path/to/storage (with TLS)
There is another backend that works with S3 compatible storage providers that require V2 signing:
s3c://region@host/bucket/path/to/storage
Wasabi
Storage URL:
wasabi://region@s3.wasabisys.com/bucket/path
wasabi://us-east-1@s3.wasabisys.com/bucket/path
wasabi://us-east-2@s3.us-east-2.wasabisys.com/bucket/path
wasabi://us-west-1@s3.us-west-1.wasabisys.com/bucket/path
wasabi://eu-central-1@s3.eu-central-1.wasabisys.com/bucket/path
Where region is the storage region, bucket is the name of the bucket and path is the path to the top of the Duplicacy storage within the bucket. Note that us-west-1 additionally has the region in the host name but us-east-1 does not.
Wasabi is a relatively new cloud storage service providing a S3-compatible API. It is well-suited for storing backups, because it is much cheaper than Amazon S3 with a storage cost of $0.0059/GB/month (see note below), and no additional charges on API calls and download bandwidth (max egress allowance is equal to storage size).
S3 and Billing
Short Version
The s3 storage backend renames objects with a copy and delete which is inexpensive for AWS but more expensive for Wasabi. Use the wasabi backend for it to be handled properly.
Long Version
Wasabi’s billing model differs from Amazon’s in that any object created incurs charges for 90 days of storage, even if the object is deleted earlier than that, and then the monthly rate thereafter.
As part of the process for purging data which is no longer needed, Duplicacy renames objects. Because S3 does not support renaming objects, Duplicacy’s s3 backend does the equivalent by using S3’s copy operation to create a second object with the new name then deleting the one with the old name. S3-style renaming with Wasabi will incur additional charges during fossilization becasue of the additional objects it creates. For example, if a new 1 GB file is backed up in chunks on day 1, the initial storage will incur fees of at least $0.0117 (three months at $0.0059 each). If the file goes away and all snapshots that contained it are pruned on day 50, renaming the chunks will create an additional 1 GB of objects with a newly-started 90-day clock at a cost of $0.0117.
The wasabi backend uses Wasabi’s rename operation to avoid these extra charges.
Snapshot Pruning
Wasabi’s 90-day minimum for stored data means there is no financial incentive to reduce utilization through early pruning of snapshots. Because of this, the strategy shown in the documentation for the prune command can be shortened to the following without incurring additional charges:
# Keep all snapshots younger than 90 days by doing nothing
$ duplicacy prune -keep 7:90 # Keep 1 snapshot every 7 days for snapshots older than 90 days
$ duplicacy prune -keep 30:180 # Keep 1 snapshot every 30 days for snapshots older than 180 days
$ duplicacy prune -keep 0:360 # Keep no snapshots older than 360 days
DigitalOcean Spaces
Storage URL:
s3://nyc3@nyc3.digitaloceanspaces.com/bucket/path/to/storage
DigitalOcean Spaces is a s3-compatible cloud storage provided by DigitalOcean. The storage cost starts at $5 per month for 250GB and $0.02 for each additional GB. DigitalOcean Spaces has the lowest bandwidth cost (1TB free per account and $0.01/GB additionally) among those who charge bandwidth fees. There are no API charges which further lowers the overall cost.
Here is a tutorial on how to set up Duplicacy to work with DigitalOcean Spaces: How To Manage Backups to the Cloud with Duplicacy | DigitalOcean
Google Cloud Storage
Storage URL:
gcs://bucket/path/to/storage
You must first obtain a credential file by authorizing Duplicacy to access your Google Cloud Storage account or by downloading a service account credential file.
You can also use the s3 protocol to access Google Cloud Storage. To do this, you must enable the s3 interoperability in your Google Cloud Storage settings and set the storage url as s3://storage.googleapis.com/bucket/path/to/storage.
Microsoft Azure
Storage URL:
azure://account/container
You’ll need to input the access key once prompted.
NetApp StorageGRID
Storage URL:
s3://us-east-1@storagegrid.netapp.com/bucket/path/to/storage
Default region is us-east-1, but others may be set in StorageGRID settings. Region must be specified in any case.
You’ll need to input an access key and a secret key to access your NetApp StorageGRID S3 storage.
Backblaze B2
Storage URL: b2://bucketname
You’ll need to enter the account id and the master application key. However, if you are using an application key to access your B2 account, you’ll need to enter the application key id and the application key instead.
Backblaze’s B2 storage is one of the least expensive (at 0.5 cent per GB per month, with a download fee of 1 cent per GB, plus additional charges for API calls).
Please note that if you back up multiple repositories to the same bucket, the lifecyle rules of the bucket is recommended to be set to Keep all versions of the file which is the default one. The Keep prior versions for this number of days option will work too if the number of days is more than 7.
Google Drive
Storage URL:
gcd://path/to/storage (for My Drive)
gcd://shareddrive@path/to/storage (for Shared Drive)
To use Google Drive as the storage, you first need to download a token file from Google Drive for Duplicacy by authorizing Duplicacy to access your Google Drive, and then enter the path to this token file to Duplicacy when prompted.
Alternatively, you can download a service account credential file which can be supplied to Duplicacy as a token file to access Google Drive. You’ll also need to add the email address of the service account to the share list of the storage directory, because by default the service account can’t access any directories/files in Google Drive.
Microsoft OneDrive
Storage URL:
one://path/to/storage (for OneDrive Personal)
odb://path/to/storage (for OneDrive Business)
To use Microsoft OneDrive as the storage, you first need to download a token file from https://duplicacy.com/one_start or https://duplicacy.com/odb_start by authorizing Duplicacy to access your OneDrive, and then enter the path to this token file to Duplicacy when prompted.
Hubic
Storage URL:
hubic://path/to/storage
To use Hubic as the storage, you first need to download a token file from Hubic for Duplicacy by authorizing Duplicacy to access your Hubic drive, and then enter the path to this token file to Duplicacy when prompted.
Hubic offers the most free space (25GB) of all major cloud providers and there is no bandwidth charge (same as Google Drive and OneDrive), so it may be worth a try.
Note that hubic no longer allows the creation of new accounts.
OpenStack Swift
Storage URL:
swift://user@auth_url/container/path
If the storage requires more parameters you can specify them in the query string:
swift://user@auth_url/container/path?tenant=<tenant>&domain=<domain>
The following is the list of parameters accepted by the query string:
- domain
- domain_id
- user_id
- retries
- user_agent
- timeout
- connection_timeout
- region
- tenant
- tenant_id
- endpiont_type
- tenant_domain
- tenant_domain_id
- trust_id
This backend is implemented using GitHub - ncw/swift: Go language interface to Swift / Openstack Object Storage / Rackspace cloud files (golang).
You can force http connections by adding the protocol argument:
swift://user@auth_url/container/path?protocol=http
Ref: Openstack swift don't support http url - #2 by gchen
WebDav
Storage URL:
webdav://username@server/path/to/storage (path relative to the home directory)
webdav://username@server//path/to/storage (absolute path with double `//`)
File Fabric by Storage Made Easy
Storage URL:
fabric://username@storagemadeeasy.com/path/to/storage
fabric://username@eu.storagemadeeasy.com/path/to/storage
Storj
Storage URL:
storj://satellite/bucket[/path]
As of April 2024, Storj no longer has a free tier, but they do offer a one month trial with 25 GB of storage. Storj pricing is $4 per GB/month.
The /path is optional. The bucket name is whatever you choose when you set up the bucket. You will also need the bucket’s encryption passphrase to connect.
To get the satellite address, log in to Storj, go to “Access Keys”, “New Access Key”, choose “API Key”, and hit “Create Access”. This will generate the satellite address along with the API Key.
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