The release of the distributed replicated block device DRBD 9.1.0 has been published, allowing for a RAID-1-like array formed from networked disks from different machines (network mirroring). The system is implemented as a module for the Linux kernel and is distributed under the GPLv2 license.
The DRBD 9.1.0 branch can be used as a transparent replacement for DRBD 9.0.x and is fully compatible at the protocol level, configuration file format, and utilities. The changes are focused on reworking the locking mechanism, aimed at reducing lock contention in the I/O handling code for DRBD. This change has improved performance in configurations with a high number of CPUs and NVMe storage by eliminating a bottleneck that negatively affected performance during a large number of simultaneous I/O requests from different CPU cores. Overall, the DRBD 9.1.0 branch is similar to the 9.0.28 release.
It should be noted that DRBD can be used to combine cluster node storage into a single fault-tolerant storage solution. For applications and systems, such storage appears as a uniform block device across all systems. When using DRBD, all operations on the local disk are sent to other nodes and synchronized with the disks of other machines. In the event of a node failure, the storage will continue to operate automatically using the remaining nodes. When the failed node becomes available again, its state will be automatically updated to the current version.
The cluster that forms the storage can consist of several dozen nodes, located both in a local network and geographically spread across different data centers. Synchronization in such branched storage systems is performed using mesh network technologies (data flows along a chain from node to node). Replication of nodes can occur in both synchronous and asynchronous modes. For example, locally located nodes can use synchronous replication, while for remote locations, asynchronous replication can be applied with additional traffic compression and encryption.
Source: opennet.ru
