# Rootfs artifact extension

**URL:** <https://hub.mender.io/t/rootfs-artifact-extension/1078>\
**Category:** General Discussions\
**Tags:** mender-artifact\
**Created:** [September 27, 2019, 8:08am UTC](https://hub.mender.io/t/rootfs-artifact-extension/1078 "2019-09-27T08:08:59Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![mirzak](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/mirzak/32/2056_2.png) [@mirzak](https://hub.mender.io/u/mirzak)\
**Post date:** [October 1, 2019, 7:13am UTC](https://hub.mender.io/t/rootfs-artifact-extension/1078/5 "2019-10-01T07:13:27Z")

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> [@RogerC](#):
>
> Ok because when I check the [Root Filesystem Image v2](https://hub.mender.io/t/root-filesystem-image-v2/402) (which is not the official one ofc) I can not see how it is possible to write at the next position in the partition with a simple cat. So I was wondering…

The [Root Filesystem Image v2](https://hub.mender.io/t/root-filesystem-image-v2/402) Update Module does not support this as you have seen as well. But the internal `rootfs-image` updater supports this as it is using HTTP range-requests to write data in chunks (1MiB), and this way it can keep track of where it is.

You take a look at the [code](https://github.com/mendersoftware/mender/blob/master/installer/dual_rootfs_device.go).

> Let’s say I want to upload a root fs partition with the A/B mechanic (i.e. a dual rootfs artifact) with the kernel inside, but I also want to upload an extra data partition at the same time (in the same artifact). The two partitions are “linked” but still dissociated on disk. That is why I was talking about extending the dual rootfs update module behavior.

Thanks for clarifying. Now I understand. In this case you have two options:

- deploy the “extra data partition” as part of the rootfs image and e.g install it in one of the Mender [state-scripts](https://docs.mender.io/2.1/artifacts/state-scripts)
- Create two separate Mender Artifacts (`.mender`) and deploy them individually.

Even though the specification of the Mender Artifact format does allow multiple payloads with different types (which what you ultimately would like I believe), this is not yet implemented in code and something that will be added further down the road.

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