Comgraphics uses VirtuCache to speed up the printing of a million PDF files

Chicago, Illinois, USA. Oct 14, 2023.

Comgraphics is a multi-platform print company, located in Blue Bell, PA and Chicago, IL.

Comgraphics wanted to speed up the printing of more than a million PDF files a day.

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.

Printing 1M+ files is a high MBps operation.

Comgraphics has deployed their printing software in VMs running in VMware and backed by Dell EqualLogic and Unity storage. These print server VMs parallel process hundreds of print jobs. When Comgraphics prints its million or so PDF files every month end, the aggregate throughput from all VMs would top a few hundred MBps. This volume of throughput cannot not be handled by their existing Dell EqualLogic and Unity appliances. The latencies would increase to many seconds when the throughput increased to a couple of hundred MBps.

How VirtuCache helps speed up Comgraphics’ large scale print server operation?

With VirtuCache installed in an ESXi host and configured to cache to in-host NVME SSD and/or RAM, when a VM does a read operation, it will be serviced from the in-host SSD / RAM, instead of the backend storage array and when a VM does a write operation, it is written to the in-host SSD / RAM. In case of VM writes, with VirtuCache in the storage I/O path, VMware acknowledges a write commit when the write is cached (written) to the in-host SSD/RAM. VirtuCache ultimately syncs the cached writes to the (slower) backend storage array, however this process doesn’t factor into a write acknowledgement, since the writes have already been committed as far as the application that runs within VM is concerned. In this fashion writes are accelerated. Print server operation is equal measure reads and writes, and by caching both reads and writes to in-host SSD and RAM, VirtuCache accelerates Comgraphics printing process considerably. Comgraphics uses a Samsung PM1735 NVME SSD which supports 200MBps of read + write throughput from within ESXi, and since each such NVME SSD is installed in each of Comgraphics’ 4 ESXi hosts, VirtuCache can support an aggregate peak throughput of 800MBps at under 5ms latency.

Customer Environment

• Dell PowerEdge rack servers running ESXi 7.
• Datastores on Dell Unity and EqualLogic storage arrays connected to ESXi hosts using 10g iSCSI.
• VirtuCache is installed in ESXi 7, and configured to cache to 1.6TB Samsung PM1725 NVME SSD in each host in a 4-host ESXi cluster. In VirtuCache, ‘Write-Back 1 Replica’ policy was applied to all the Datastores. ‘Write-Back 1 Replica’ policy caches all reads and writes to in-host cache media (in this case host NVME SSD) and mirrors the write cache to cache media in another host in the same cluster.