LINBIT, the reference in Linux Data Protection

LINBIT, the reference in Linux data protection, joined the recent 47th IT Press Tour organized in Lisbon, Portugal. It was the opportunity to get an update about DRBD, the famous Distributed Replicated Block Device engine, directly from the CEO and founder of LINBIT, Philipp Reisner, who started this project during his studies more than 20 years ago.

Since that, the company has launched another product named Linstor, with a portion of the company name in the product name. Perhaps a recognition of the disconnect between a recognized product and an unknown company, people having difficulties to associate the two. will publish an article later about Linstor but also LINBIT SDS, HA and DR.

LINBIT was founded in 2001 in Austria without any VC and employs around 35 people today. The company is profitable and fully owned by its founder.

I mentioned DRBD as a famous solution by the simple fact that the product is deployed more than 2 million times. It is used by large well known brands like Amazon, Apple, Cisco, Google, IBM, Intel, Oracle, Red Hat or Yahoo!.

So let’s cover today DRBD as the preferred block level replication for Linux. As a block oriented engine, the copy engine works above any block device, physical or logical, and below the file system layer. A block device could be a single partition, a LVM volume, a MD volume with 0, 1, 4, 5, 6 or 10 assembly mode, a VDO (Virtual Data Optimizer from Permabit acquisition) entity or a zVol from ZFS with different flavor. DRBD supports any initiators and targets supported by Linux such LIO, STGT, SCST, Ietd, iSCSI and of course NVMe-oF and especially TCP. It offers synchronous and asynchronous mode and up to 32 replicas with version 9.x on any TCP/IP network.

The mode can be mixed between one source and its targets. Multiple primaries are also possible for cluster needs like GFS or OCFS2. Cascading is not supported yet but as multiple replicas are possible users can build interesting configurations but still add load on the primary. Users can even configure the engine to be diskless at the source copying memory data to remote devices. The engine implements partial resync to only consider blocks not already present or synchronized. The replication can work in multiple directions with only one master source at a time except on some specific use cases such cluster mentioned above or live migration of VMs. During a failover, the unmount of file system then detach of volume triggers the source to release its primary role and vice-versa, as soon as a volume is locally attached and the file system is mounted, the initiator is set and the replication direction is decided. But LINBIT protects this and only one source can be active at a time preventing data corruption, except the 2 cases listed above.

The team has launched a Windows flavor, currently in 1.0 released in Q1/2022 supporting Windows 7SP1, Windows 10, Windows Server 2008, 2016 and 2019.

DRBD 9.0 and 9.1 can be downloadable here, the 9.2 announced October 10 is also available there.

Again a very good deep session presented by the master Reisner.