The Virtunet DifferenceVirtuCache caching 'hot' data from AiG's existing HP Store VSA storage to in-VMware host SATA SSD + 50GB host RAM performed 5x better than HP Store VSA's tiering functionality (called HP Adaptive Optimization).
The Ark Encounter, in Williamstown, Kentucky, features a full-size Noah’s Ark built according to the dimensions of the Bible. Answers in Genesis (AiG) is the Christian ministry responsible for The Ark Encounter.
AiG’s IT department had a few ESXi hosts connected to their HP Store VSA. As a result of increased attendance at the Ark, their VMware workload increased dramatically, which in turn resulted in performance issues within VMs.
AiG turned to VirtuCache to mitigate their storage latency issues. By caching frequently and recently used data (both reads and writes) to in-host SSDs+RAM, Virtunet resolved their storage performance issues. We competed with HP Store VSA’s Adaptive Optimization(AO) feature, which is HP’s tiering functionality for the VSA.
Here is how VirtuCache competes with the Store VSA’s tiering functionality.
HP VSA Adaptive Optimization(AO) accelerates only reads, VirtuCache accelerates both reads and writes. Since AO is tiering technology, it moves frequently accessed data to faster tiers, and hence it only improves read performance. The writes don’t go through the faster SSD tiers. Compare this with VirtuCache where both reads and writes are cached to the in host SSD and/or RAM.
AO is not realtime. It promotes data to faster tiers by analyzing storage IO patterns over time. In comparison VirtuCache immediately moves a block to the SSD when it is accessed for the first time. We do this because we assume that if the block is read once, it is more likely that it will be read again versus other blocks. Also with VirtuCache all recent writes are written to the SSD. As a result, bursty workload that is highly random is better serviced by VirtuCache than with HP AO. Since VMware workloads are highly random, VirtuCache is more effective for VMware workloads than HP AO.
HP VSA AO can only use SSD or HDD as tiering media. VirtuCache can use SSD and/or RAM as cache media. In the case of AiG, we used 50GB of host RAM with a slower SSD as cache media. Adding some amount of RAM to a SSD in VirtuCache helps mask the performance of the SSD. In this situation ‘hotter’ data is cached to RAM, and less ‘hot’ data is cached to SSD.
Because of all the above reasons, VirtuCache performed at 5x the speeds of HP VSA AO.
Tony Ramsek, IT manager for the AiG with Nina Fletcher, Account Manager for Virtunet Systems