DRBD, developed by LINBIT, provides networked RAID 1 functionality for GNU/Linux. It is designed for high availability clusters and software defined storage. DRBD keeps disks on multiple nodes synchronized using TCP/IP or RDMA and makes the data available as a block device. This results in RAID 1 but without the use of uncommon hardware such as shared SCSI buses or Fibre Channel.

This repository contains the Linux kernel code for DRBD version 9 and above.

Please read the user-guide provided at docs.linbit.com.

For further products and professional support, please contact us.

Development is coordinated via mailing lists. Currently, we do not intend to use github issue tracking/github PRs.

Since version 9.0.20, DRBD has been using a kernel backwards compatibility system based on Coccinelle semantic patches. While this has many advantages, it also makes it a little harder for "casual" developers to build DRBD from the git sources. The problem is that we require a very recent version of spatch (at least 1.0.8 at time of writing), and most distributions only have relatively old versions in their repositories.

For users wishing to build DRBD from its git sources, here are a few options:

1. Use a recent kernel. When building against a recent(ish) upstream kernel, chances are you won't even have to use any of the compat features, which means you won't require compatibility patches and in turn don't need spatch installed.
2. On Ubuntu 18.04 and newer, use a recent spatch version from the Coccinelle PPA. This provides (at time of writing) version 1.0.8, which is recent enough to build DRBD.
3. Build and install spatch from source. This will also give you a version that is recent enough to build DRBD.

For use cases where it is appropriate to just build DRBD from a release tarball, here are some options:

1. Use a distribution kernel and rely on the shipped "compat patch cache". We pre-generate compatibility patches for a list of commonly used distribution kernels and ship them with every release tarball. If your kernel matches one of those in the cache, you won't need spatch because the cached patch will be applied directly.
2. For all other kernels, you can use LINBIT's "spatch as a service" online service, which transparently and automatically generates compatibility patches based on your kernels feature set.
3. If you are using an exotic kernel and you do not have internet access or otherwise can't or don't want to use "spatch as a service", you will have to install a recent version of coccinelle (see above).

For a release tarball, these options should be handled transparently for the user. In other words, if you download a tarball and type "make", it should work in next to all cases.

Releases generated by git tags on github are snapshots of the git repository at the given time. You most likely do not want to use these. They might lack things such as generated man pages, the configure script, and other generated files. If you want to build from a tarball, use the ones provided by us.