The Virtunet DifferenceThe customer selected VirtuCache because:
Kralendijk, Caribbean Netherlands. August 1,2022.
Bonaire, a municipality of the Netherlands, is a beautiful island in the Caribbean.
Their public utilities department, Water- en Energiebedrijf Bonaire N.V. a.k.a Webbonaire, is a customer of VirtuCache. They use VirtuCache to improve the performance of their Scada applications, which run in VMware VMs with a Synology All-Flash appliance as primary storage.
Virtunet Systems develops VirtuCache software. VirtuCache improves the storage performance of VMware VMs by caching all VM read and write operations to in-host SSD or RAM.
High VMware Disk Latency in Synology Appliance because of a Weak Controller
Synology appliances that Webbonaire uses are all-Flash appliances, yet they were experiencing high disk latencies. This was because the controllers on these appliances are not very powerful. To keep the Synology appliances reasonably priced, the controller processors in these appliances are dual core Intel processors. As a result, the controller chokes when large amount of small block IO are transmitted through it, as was the case at the customer.
How VirtuCache Reduces Latencies for Synology Appliances
VirtuCache automatically caches all storage IO (reads and writes) from VMware VMs to ESXi host SSD or RAM. So, any reads requested by VMware VMs are serviced from in-host SSD or RAM and all writes from VMs are written to the same in-host SSD / RAM as well. So, the storage IO processing is offloaded from SAN array controllers to ESXi host CPUs. Since ESXi host CPUs are considerably more powerful and usually are underutilized, this strategy of using VirtuCache to relieve pressure on SAN array controllers and improve IOPS and latencies works very well for Synology appliances.
- HP Gen10 servers running ESXi 7.0.
- Datastores on Synology FS6400 storage arrays connected to ESXi hosts using 10g iSCSI.
- VirtuCache was installed in ESXi 7 in each host, and it was configured to cache to in-host 3.2TB Samsung PM1735 PCIe SSD in each host in their 3-host ESXi cluster. In VirtuCache, ‘Write-Back One Replica’ policy was applied to all the Datastores. ‘Write-Back One Replica’ policy caches all reads and writes to in-host cache media and mirrors the write cache to cache media in one more host in the cluster. As a result, all reads and writes are serviced directly from the in-host cache media without involving the backend storage arrays, thus improving storage latencies considerably.