September 1st, 2015 by Adam Armstrong
VMware Announces VSAN Beta
There have been a lot of announcements at VMworld this year. A major announcement was the upcoming release of VSAN 6.1, with its new features such as Stretched Cluster, Virtual SAN for ROBO, Replication with vSphere Replication, and so on. Another major announcement is a limited beta for future VSAN releases in order to test upcoming technology. The beta will be focused on two technologies: space efficiency and advanced data integrity.
VSAN delivers high performance, simplicity, scalability, reliability, and high availability (of their 2,000+ customers, they have yet to report a loss of data from a VSAN in production). However, in order to get the high availability data has to be mirrored across nodes at the expense of space efficiency. The new technologies that VMware plans on implementing could increase usable capacity by up to 16 times while still delivering the same levels of availability.
VMware is looking at space efficiency through deduplication and erasure coding. The new VSAN will be testing deduplication applied on a per-Disk-Group basis, ensuring that users still enjoy the benefits of fine-grained, policy-based management. While deduplication will most likely affect performance (this will vary with workload) but it can give users up to 8 times the usable capacity.
Along with deduplication, VMware also plans on testing erasure coding with RAID 5 and RAID 6 options. That means the 2x overhead from simple mirroring would drop to 1.33x when users want to tolerate a single failure (FTT=1). For FTT=2, the overhead would drop from 3x to 1.5x. Meaning that with no hardware changes, users could see up to 50-100% increase in usable capacity. Combining erasure coding with deduplication, users could potentially see usable capacity increase by 16 times.
VMware also plans on testing an end-to-end software checksum in the beta to ensure data integrity. Using CRC32c and utilizing special CPU instructions thanks to Intel, the software checksum will help to protect against storage bit rot, network problems, software and firmware issues. The software checksum will complement existing hardware checksums and will be compatible with all VSAN data services.
Customers who wish to test the beta can signup in the link below (there is a limited amount of beta users).