Software defined storage (SDS) continues to struggle for relevance in a crowded storage marketplace. While a few products are gaining a following, many more have either failed or been sold to other vendors. Additionally, now operating systems also pose a real threat to SDS’ value and its future.
Most operating systems provide the same core functionality as most SDS solutions. Linux poses a particular threat to SDS. It offers very mature volume management, protection from media failure (RAID), thin provisioning, and snapshots. Linux also offers built in SSD (Solid State Drive) cache technology. Additionally, it now provides one of the best deduplication technologies on the market, thanks to Red Hat’s acquisition of Permabit’s Virtual Data Optimizer (VDO). Red Hat is GPLing (General Public Licensing) it, preparing VDO for Linux upstreaming.
Linux also supports the system acting as a target mode block device. Currently Linux can act as a target for iSCSI, FC, and FCoE protocols. It even recently added NVMe over Fabric support (NVMe-oF).
What’s Missing? High Availability (HA) and Orchestration
The only capabilities missing to make a Linux server a viable standalone storage system is HA and orchestration of the various features. LINBIT with DRBD and LINSTOR promises to fill those gaps.
For a storage system, HA moves the concept of internal protection from media failure (RAID) outside of the system, protecting the organization’s data from both media and server failure. Some solutions add replication to move data outside the data center, adding protection from site failure.
DRBD is often thought of in a server context, with server-to-server replication protecting against server failure. The storage context uses DRBD to protect the organization’s data from the failure of a Linux storage server. A Linux server armed with its core features and DRBD provides most, if not all, of the same capabilities as an SDS solution or even a proprietary storage system.
One final missing component is orchestration. While Linux can claim feature parity with most SDS systems, it achieves that parity by individual utilities. The administrator needs to manage each utility separately. LINBIT’s LINSTOR is essentially an orchestration engine, controlling Linux’s various utilities like volume creations, snapshots, thin provisioning, caching and of course DRBD.
LINSTOR aims to build storage systems from generic (x86) nodes without recreating all the components that Linux already provides. LINSTOR deploys on distinct storage nodes or hyperconverged with Linux hypervisors or containers.
LINSTOR connects to the environment via “northbound” drivers, which enables those environments to control LINSTOR directly from that environment. Today the solution works with OpenStack Cinder, Kubernetes, OpenNebula, Proxmox, XenServer and the native Linux command line. LINBIT is also set to add support for SNIA’s Swordfish API and is hinting at a Windows port.
While there are other Linux based SDS applications available on the market, LINSTOR’s advantage is in its simplicity and being Open Source. Instead of replacing existing well vetted utilities that already exist in the Linux distribution, it manages and orchestrates them. LINSTOR then adds to those utilities DRBD+Pacemaker for replication and HA. This method of implementing SDS should result in a less expensive but more scalable and hardened solution. It also enables LINBIT to continue to innovate faster than its competition since it doesn’t have to re-create, and subsequently maintain, all the necessary but already existing components.
What if an SDS solution, instead of replacing capabilities that were already in the operating system, simply added capabilities that were not there and then knitted those utilities together for seamless operation? In the case of a robust operating system like Linux, the SDS solution only needs to add shared access to data and orchestration of the various storage utilities that Linux already provides. LINBIT is delivering LINSTOR to add orchestration and control to what Linux, with the addition of DRBD, already provides.