VirtuCache is installed in VMware vSphere kernel. It then automatically caches frequently and recently used data from any backend storage to any high speed media (RAM/SSD) in the VMware host. By bringing large amounts of 'hot' data closer to the VMware host GPU and CPU, VirtuCache improves the performance of all applications running within VMs including GPU assisted operations.
End users of these virtual desktops complained about slow boot times, Windows cursor and start button freezing and generally slow response times from the virtual desktops at various times during the day.
VirtuCache was deployed on each of the physical hosts with Seagate SATA SSDs. VirtuCache was configured to cache LUNs on their HP EVA and Xiotech appliances to a single 480 GB Seagate 600 Pro SATA SSDs installed in each of their ESXi hosts.
The chart below shows maximum latencies before and after VirtuCache for each of the VMs on the host for two consecutive Mondays. Performance data for the ESXi host shown in this graph is a representative example of the extent to which performance of each host in the cluster was improved.
By using VirtuCache with a single 480 GB Seagate enterprise SATA SSD, peak VM level latencies were reduced by a fourth or less. We ensured that maximum VM latency at all times remained under 20 milliseconds.
CEPH is fast becoming the most popular open source storage software. However it's one drawback is high latency. Host side caching software installed in VMware hosts which can cache 'hot' data from CEPH volumes to in-VMware host SSD or RAM can be used to overcome this deficiency in CEPH. We believe that this use case for host side caching software will allow CEPH to be used for latency sensitive on-premise situations.
Pros of CEPH storage.
CEPH storage software can be installed on any commodity servers. It clusters servers together and presents this cluster of servers as an iSCSI or NAS appliance. You can build CEPH storage with any server, SSD, HDD, NIC, essentially any server or server part. There is no vendor lock-in for hardware. As a result, hardware costs are low. If you want to scale up storage capacity, you can keep adding servers to this cluster, with storage capacity and performance scaling linearly as you add servers. You manage this cluster, however large, with a single GUI. All in all, it offers better reliability and deployment flexibility at a lower cost than big brand storage appliances.
One drawback of CEPH.
The one drawback with CEPH is that write latencies are high even if one uses SSDs. By deploying VirtuCache which caches hot data to in-host SSDs, we are able to get All-Flash array like latencies for CEPH storage built using slow SATA hard drives.
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, along with The Creation Museum, in nearby Petersburg, Kentucky.
AiG's IT department had a few hosts spread across The Ark and The Creation Museum. Their VMware hosts were connected to HP LeftHand Networks appliances. As a result of increased ticket sales and new development projects at the The Ark and The Creation Museum, 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 used data to in-host SSDs, Virtunet immediately resolved their storage performance issues and without requiring AiG to upgrade any of their SAN or storage equipment.