Virtual SAN (VSAN) was released two years ago and I think it is fair to say that the initial release was never going to “set the world on fire”, but roughly every six months a new version appeared with a huge list of improvements. This brings us to the recently announced 6.2 release, which for me is the first version that is ready for mainstream adoption – highlights include:
- De-duplication – 4K blocks within a disk group with the process occurring when the blocks are de-staged to the capacity tier (All-Flash only)
- Compression – attempts to reduce de-duplicated 4K blocks down to 2K or less (All-Flash only)
- RAID 5/6 – in addition to the existing RAID 1 (All-Flash only)
- Checksum data integrity on reads and periodic scans
- Quality of Service IOPS Limits (per VM)
- In memory Read Cache
One of the things I really like about this new release is that the RAID policy is a function of the VM – within the same cluster you could have VMs that are performance optimised (RAID 1), availability optimised (RAID 6) and balanced (RAID 5).
Licensing is typically per-socket and there are three editions:
- Standard – includes all core features
- Advanced – adds All-Flash, De-duplication & Compression, and RAID 5/6
- Enterprise – adds Quality of Service IOPS Limits and Stretched Cluster
So when should you consider VSAN?
- General vSphere environments – as you can start small and grow as needed
- Virtual Desktops – all-flash is optimal, de-duplication will have a big impact and at scale you can take advantage of RAID 5/6
- Databases and other ultra high IO VMs – generally a relativity small amount of flash is required and the applications benefit from de-duplication and/or compression
- Simple stretched clusters – to enable vMotion and HA between sites for vastly improved Business Continuity (and no need for Site Recovery Manager)
The next key question is do you go software-defined or with a hardware appliance? This really comes down to:
- Do you want a turn key solution with a single point of support for all hardware and software (see VxRail post)
- Do you want the maximum flexibility in choosing and upgrading your server hardware (a true software-defined solution)
In the early days of VSAN I thought it was not ready for mainstream adoption, but the progress VMware has made over the last two years has been nothing short of staggering. Any vSphere customer who is considering a Hyper-converged platform, Virtual Desktop storage, a Stretched Cluster or an All-Flash Array should take a serious look at VSAN.
- EVO:RAIL is dead long live VxRail
- An introduction to VMware Virtual SAN Software-Defined Storage technology
- Enabling 24×7 Continuous Availability with a vSphere Metro Storage Cluster