Since version 22.1, Canister supports Spanning; when a source won't fit the mounted tape, Canister will ask you if you want to span your data across multiple tapes.
You can use both preformatted tapes and non-formatted tapes. If a tape isn't formatted, Canister will prompt to format during the Spanning process.
When starting a Spanning transfer, you can add a Spanning Label to make it easy to find your spanned data later in the Catalog:
How Canister's spanning works is described in depth on our blog: https://blog.hedge.video/s-is-for-spanning/

As with all things LTO, stuff happens. Where with hard disks it's easy to redo something, due to LTO's linear nature, errors tend to be showstoppers - at least temporarily. When spanning the chance that a tape runs into an issue or that an archive fails for some reason, is of course compounded.
Canister gets around this problem by using its Dupe Detection implementation to the fullest: in case an error happens with any tape during a spanning archive, simply start over. Select the source, mount the first tape, and start the archive. Canister will automatically understand tape 1 is full, and ask for the next. Rinse, repeat.
It's important to feed Canister all tapes that were finished properly, and then feed it the tape that had the error. If the tape still mounts, Canister will proceed as is. If not, Canister will offer to format the tape, and then you're back on track.

When using a tape library instead of a desktop LTO drive, format all LTO tapes before starting with spanning data. Due to how libraries work with LTFS, Canister currently cannot offer mid-transfer formatting of new tapes.
Last modified 3mo ago
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