Currently the header (header.tar.gz) and updates (e.g. data/0000.tar.gz, data/0001.tar.gz) in Mender Artifacts are assumed to be compressed (with .gz). See the Artifact format specification for more details.
However lower-end devices like microcontrollers have a challenge working with compressed data due to constrained resources. See this community list thread for more information: https://groups.google.com/a/lists.mender.io/forum/#!topic/mender/iW53Wc0na0w
For this reason it would be nice if it was possible to support uncompressed tar files as well (e.g. data/0000.tar, data/0001.tar).
Since the mender artifact library (and thus Mender server) computes the checksum of the inside of this tar file (the rootfs image), this requires some changes in the mender-artifact library.
It is possible to use uncompressed .tar files as updates It is possible to use uncompressed .tar files in the header (header.tar, instead of header.tar.gz)
This has been implemented by a contributor in https://github.com/mendersoftware/mender-artifact/pull/150. The new acceptance criteria are:
- Update vendor dependencies in deployments service
- Make one end-to-end test that uploads and updates using an uncompressed artifact (reuse and tweak existing test probably)
- Add a section somewhere in the docs to explain that uncompressed artifacts are possible.
Reestimated to 5 due to help from outside.