Backup regions, bucket names & target URLs

multiback/mybackup construct the bucket name and the Duplicity target URL deterministically per backend. You do not pick the bucket name; you create a matching bucket up front where the provider requires it.

Bucket name construction

_construct_bucket_name builds:

TXT

back-to-<user>-<hostname-with-dots-as-dashes>-<service-with-underscores-as-dashes>

<user> — the path-set selector: global, data or custom root-side, or the tenant's o### user.
<hostname> — _hName read from /etc/hostname (falling back to hostname -f), dots replaced with dashes. Verify with cat /etc/hostname, not uname -n — the two can differ and only /etc/hostname is used.
<service> — the backend key with underscores replaced by dashes (aws_one_zone becomes aws-one-zone).

Example: tenant o123 on fr8.eu.aegir.cc to Wasabi gives back-to-o123-fr8-eu-aegir-cc-wasabi. The underscore-to-dash swap applies only inside the bucket name; the credential file keeps the underscored key (do_spaces.txt).

The legacy tools use their own host-wide names: backboa uses daily-boa-<host-with-dashes>, duobackboa uses daily-remote-<host-with-dashes> (see Legacy backboa).

Per-backend target URLs

_set_backup_target builds the Duplicity URL, interpolating the credential values per backend (the passphrase is never here — it is the separate PASSPHRASE env var):

Backend key	Target URL form
`aws` / `aws_one_zone` / `aws_standard_ia`	`boto3+s3://<bucket>` plus `--s3-endpoint-url https://s3.dualstack.<region>.amazonaws.com --s3-region-name <region>` (the two IA variants add `--s3-use-ia`)
`azure`	`azure://<storage-account>@<bucket>`
`b2`	`b2://<account-id>:<application-key>@<bucket>` (both URL-encoded)
`cloudflare`	`boto3+s3://<key>:<secret>@<account>.r2.cloudflarestorage.com/<bucket>`
`do_spaces`	`s3://<key>:<secret>@<region>/<bucket>`
`gcs`	`gs://<bucket>`
`ibm`	`ibmcos://<api-key>:<service-instance>@<region>/<bucket>`
`linode`	`s3://<access-key>:<secret-key>@<region>/<bucket>`
`wasabi`	`s3://<access-key>:<secret-key>@<region>/<bucket>`

The region comes from the backend's own region variable in the credential file (AWS_REGION, DO_SPACES_REGION, LINODE_REGION, WASABI_REGION, IBM_REGION) — Cloudflare R2 is region-less (geographic placement is automatic), and B2/Azure/GCS take the region from the account, not the URL.

Bucket auto-creation policy

Most providers auto-create the bucket on first write if credentials have permission. Several do not and must have the bucket created by hand first:

Provider	Auto-create	Action
Wasabi	Yes	none
Backblaze B2	Yes	none
DigitalOcean Spaces	Yes (write perms)	none
Google Cloud Storage	Yes (write perms)	none
Microsoft Azure Blob	Yes	none
AWS S3	Unreliable	create manually (region propagation delays)
Cloudflare R2	Not supported	create manually before first backup
IBM Cloud Object Storage	Not supported	create manually before first backup
Linode Object Storage	Not supported	create manually before first backup

When creating by hand, use the exact constructed name (back-to-<user>-<hostname-with-dashes>-<service-with-dashes>) in the provider console, keep the bucket private (BOA uses per-account credentials, not bucket ACLs), and pick the region closest to the host.

Connectivity test

After credentials and (where required) the bucket are in place, verify with the test action — it runs duplicity cleanup --dry-run --timeout 8 and reports whether it can reach the bucket:

multiback test wasabi data

test failure messages distinguish a missing/wrong-named bucket from a backend-connection failure. mybackup has no test action (its only verb is restore); a tenant's connectivity is exercised through the root-side scheduled run.

Choosing a region

Match the host's geographic region for lower restore latency and egress.
Avoid cross-continent destinations unless data-residency requires it.
A single-region account per host is sufficient; provider-level cross-region replication is overkill for this use case.

Region codes per backend

The region code is provider-defined reference, not a value BOA validates. multiback interpolates whatever the credential file's region variable holds straight into the target URL in _set_backup_target, with no allowlist, so a wrong or misspelled code surfaces only when the test action tries to reach the bucket. For Wasabi, DigitalOcean Spaces, Linode and IBM the code is the value for WASABI_REGION, DO_SPACES_REGION, LINODE_REGION and IBM_REGION; for Backblaze B2, Azure and Google Cloud Storage the target URL carries no region, so the code is what you choose when you create the account or bucket at the provider. Cloudflare R2 has no region — placement is automatic, with optional location hints.

These are provider-defined lists that grow as each vendor opens new data centres, so treat the tables below as a snapshot rather than an allowlist and check the linked provider reference for the current set. The Google Cloud Storage, Azure and IBM tables are partial to begin with; the others track each provider's full published list at the time of writing. The AWS S3 backend uses the standard AWS region names (us-east-1, eu-central-1, …); its full accepted set is enumerated under Legacy backboa.

Wasabi

Data centre	Region code
Virginia, USA	`us-east-1`
Virginia, USA	`us-east-2`
Oregon, USA	`us-west-1`
Plano, Texas, USA	`us-central-1`
Toronto, Canada	`ca-central-1`
London, England	`eu-west-1`
Paris, France	`eu-west-2`
Amsterdam, Netherlands	`eu-central-1`
Frankfurt, Germany	`eu-central-2`
Milan, Italy	`eu-south-1`
Tokyo, Japan	`ap-northeast-1`
Osaka, Japan	`ap-northeast-2`
Singapore	`ap-southeast-1`
Sydney, Australia	`ap-southeast-2`

Current list: Wasabi storage regions.

Backblaze B2

Data centre	Region code
Amsterdam, Netherlands	`eu-central`
Reston, Virginia	`us-east`
Sacramento, California	`us-west`
Stockton, California	`us-west`
Phoenix, Arizona	`us-west`
Toronto, Ontario	`ca-east`

B2 derives the region from the account, so the b2:// target URL carries no region and these codes are informational only. The region is fixed when you create the B2 account and cannot be changed afterwards — to back up to more than one B2 region you need a separate B2 account per region. Current list: Backblaze B2 data regions.

DigitalOcean Spaces

Data centre	Region code
New York City, United States	`nyc3`
San Francisco, United States	`sfo2`
San Francisco, United States	`sfo3`
Amsterdam, Netherlands	`ams3`
Singapore	`sgp1`
London, United Kingdom	`lon1`
Frankfurt, Germany	`fra1`
Toronto, Canada	`tor1`
Bangalore, India	`blr1`
Sydney, Australia	`syd1`

Current list: DigitalOcean regional availability.

Google Cloud Storage

GCS takes its location from the bucket, not the target URL; the code is set when the bucket is created. Partial list:

Data centre	Region code
Iowa (US Central)	`us-central1`
South Carolina (US East)	`us-east1`
Northern Virginia (US East)	`us-east4`
Oregon (US West)	`us-west1`
Los Angeles (US West)	`us-west2`
Salt Lake City (US West)	`us-west3`
Las Vegas (US West)	`us-west4`
Montreal (Canada)	`northamerica-northeast1`
São Paulo (South America)	`southamerica-east1`
Santiago (South America)	`southamerica-west1`
Finland (Europe)	`europe-north1`
Belgium (Europe)	`europe-west1`
London (Europe)	`europe-west2`
Frankfurt (Europe)	`europe-west3`
Netherlands (Europe)	`europe-west4`
Zurich (Europe)	`europe-west6`
Warsaw (Europe)	`europe-central2`
Sydney (Australia)	`australia-southeast1`
Jakarta (Indonesia)	`asia-southeast2`
Singapore	`asia-southeast1`
Taiwan	`asia-east1`
Hong Kong	`asia-east2`
Tokyo	`asia-northeast1`
Osaka	`asia-northeast2`
Seoul	`asia-northeast3`
Mumbai	`asia-south1`
Delhi	`asia-south2`

Current list: Cloud Storage locations.

Azure Blob Storage

Azure takes the region from the storage account, not the target URL. Partial list:

Region name	Region code
East US	`eastus`
East US 2	`eastus2`
Central US	`centralus`
North Central US	`northcentralus`
South Central US	`southcentralus`
West US	`westus`
West US 2	`westus2`
West US 3	`westus3`
Canada Central	`canadacentral`
Canada East	`canadaeast`
Brazil South	`brazilsouth`
Brazil Southeast	`brazilsoutheast`
Europe North	`northeurope`
Europe West	`westeurope`
France Central	`francecentral`
France South	`francesouth`
Germany North	`germanynorth`
Germany West Central	`germanywestcentral`
Switzerland North	`switzerlandnorth`
Switzerland West	`switzerlandwest`
UK South	`uksouth`
UK West	`ukwest`
Australia East	`australiaeast`
Australia Southeast	`australiasoutheast`
Australia Central	`australiacentral`

Current list: Azure geographies.

IBM Cloud Object Storage

Partial list:

Region name	Region code
US Cross Region	`us`
US South (Dallas)	`us-south`
US East (Washington DC)	`us-east`
EU Cross Region	`eu`
EU Central (Frankfurt)	`eu-de`
EU North (Oslo)	`eu-north`
EU West (Milan)	`eu-it`
Asia Pacific Cross Region	`ap`
Asia Pacific North (Tokyo)	`jp-tok`
Asia Pacific South (Sydney)	`au-syd`

Current list: IBM Cloud Object Storage endpoints.

Akamai (Linode) Object Storage

Data centre	Region code
Amsterdam, Netherlands	`nl-ams-1`
Atlanta, GA, USA	`us-southeast-1`
Chennai, India	`in-maa-1`
Chicago, IL, USA	`us-ord-1`
Frankfurt, Germany	`eu-central-1`
Jakarta, Indonesia	`id-cgk-1`
Los Angeles, CA, USA	`us-lax-1`
Madrid, Spain	`es-mad-1`
Miami, FL, USA	`us-mia-1`
Milan, Italy	`it-mil-1`
Newark, NJ, USA	`us-east-1`
Osaka, Japan	`jp-osa-1`
Paris, France	`fr-par-1`
São Paulo, Brazil	`br-gru-1`
Seattle, WA, USA	`us-sea-1`
Singapore	`ap-south-1`
Stockholm, Sweden	`se-sto-1`
Washington, DC, USA	`us-iad-1`

Current list: Akamai object storage.

Cloudflare R2

R2 has no region variable; placement is automatic. Optional location hints bias where data is stored (best-effort, not guaranteed):

Region	Location hint
Western North America	`wnam`
Eastern North America	`enam`
Western Europe	`weur`
Eastern Europe	`eeur`
Asia-Pacific	`apac`
Oceania	`oc`

Current list: R2 data location hints.

multiback operations — credential files that feed these URLs.
CLI reference — the test verb.
Legacy backboa — the daily-boa-<host> AWS-only scheme and the full _AWS_REG region list.