- Dell R720 servers running ESXi 6.0.
- 20 TB of Equallogic and 10 TB of Tegile storage over 1gbps iSCSI.
- End users were complaining about cursor freezes, long boot times, jittery video and audio, and general slowness in their desktop VMs.
- Also they could benefit from improved performance from their SCADA server VMs.
- Write-Through caching policy was applied to all Datastores.
- An Intel P3600 PCIe SSD was used in each host as cache device.
The Virtunet DifferenceVirtuCache caching to Intel P3600 NVME/PCIe SSDs was able to ensure under 5 ms latencies at all times from within all their desktop and server VMs.
Fairbanks Sewer and Water (FSW) wanted to improve the performance of their server VMs (especially their server VMs running SCADA) and Horizon View virtual desktop VMs. Their virtual desktop VMs were exhibiting all the classic symptoms of storage related issues – cursor freezes, long boot times, long VM provisioning times, jittery audio/video.
VirtuCache deployment details:
VirtuCache was installed on each of their four hosts running vSphere 6.0. A 1.2 TB Intel DC P3600 PCIe SSD in each VMware host was configured as cache device.
VirtuCache was configured to cache at the Datastore level, versus at the VM level. As is typical in most VMware environments, FSW had many server and VDI VMs, but only a few Datastores, so it was much quicker for them to assign caching policy to a few Datastores than hundreds of VMs. These Datastores were spread across their WD Tegile and Dell Equallogic iSCSI SAN
Write-Through caching policy caches only reads (and not writes) and it was applied to all Datastores. FSW decided to apply Write-Through caching policy and not Write-Back policy because they had a congested 1gbps network that prevented them from using it for VirtuCache’s write replication feature. Write replication is a process in VirtuCache that synchronously replicates write cache to cache media in another host. This is to prevent data loss in case a host fails.
The Intel P3600 PCIe SSD, though not the lowest latency SSD on the market for write performance (50K random IOPS rating), was very good at random read performance (450K random IOPS). Since VirtuCache was deployed in Write-Through mode, the write performance of the SSD was not very critical.
Note that newer NVME SSDs that come in PCIe form factor (and not the newer 2.5″ NVME form factor) are compatible with earlier generations of PCIe slots in older servers, and so FSW didn’t need a NVME slot in their server, which typically is a configuration option only in new servers (as of 2019).
FSW have been running VirtuCache in production since December 2017.
Signup for the VirtunetSystems Newsletter