Storage cluster management with LINSTOR

Digital Warehouse

LINSTOR open source software manages block storage in large Linux clusters and simplifies the deployment of high availability with distributed replicated block device version 9 (DRBD 9), dynamically provisioning storage and simplifying storage management for Kubernetes, Docker, OpenStack, OpenNebula, and OpenShift through integration. Alternatively, the software can take care of high availability with DRBD exclusively. In this article, I look into the setup and operation of the tool.

At first glance, storage automation appears to be a simple problem: It's been a long while since the tasks of creating, enlarging, and deleting storage volumes were subject to the restrictions imposed by the size of individual storage devices or the size and position of the slices or partitions created on them. Technologies such as the Logical Volume Manager (LVM) or the Zetabyte filesystem (ZFS) have long made it possible to manage storage pools in which almost any number and any size of storage volume can be created or deleted with equal ease.

At first glance, it might seem easy enough to automate these manual tasks with a few scripts. However, automation requires attention to tiny details and holds many potential pitfalls for the admin, as well. What is not noticeable in manual administration can quickly lead to problems in automation – for example, when device files do not yet exist in the /dev filesystem, even though the respective command for creating a volume has already reported completion, or if you want to delete volumes that are no longer mounted but are in use by the udev subsystem. If the requirement to manage an entire cluster centrally, and not just a single system, is added, it is clear that a few rough-and-ready scripts are not up to the task.