PrimoCache is caching software for Windows servers and workstations that can use DRAM and/or SSD to speed up both read and write opeartions. PrimoCache has two levels of cache – level-1 is DRAM and level-2 is SSD. A 90-day trial version can be downloaded from Romex Software website.
Main Features (source Romex Software website)
- Supports physical memory, solid-state drives and flash drives as cache storage.
- Implements a two-level caching architecture.
- Supports persistent level-2 caching.
- Supports Write-Through and Write-Deferred caching modes.
- Supports TRIM command.
- Supports OS Invisible Memory.
- Implements an intelligent and self-tuning cache replacement algorithm.
- Supports caching strategies: Read/Write Caching, Read-Only Caching and Write-Only Caching.
- Supports performance statistics and monitor.
- Supports caching for multiple volumes
- Supports caching for volumes with proprietary file system.
- Supports caching for volumes on basic and dynamic disks.
- Supports plug and play.
- Supports command-line interface.
Testing and results
For testing I selected a virtual machine which is running some management software with integrated mysql db server. For some reason mysql was causing heavy read IO – 2000 to 3000 iops. I created a 4GB read-only cache. After 30 minutes cache was warmed and mysql was no longer stressing the storage array. Cache hit rate is almost 100% with 1,76GB of cache still free.
From VMware performance charts it is visible that read IO dropped almost to zero.
Read IOPS also disappeared.
Other use case
Write-deferred cache will turn small random IOs into large sequential IOs. This caching option could potentially speed up non-ssd disks which are not that great for small random writes.
PrimoCache is licensed per PC/server. Non-commercial license starts at $29.95, business license starts at $119. License includes lifetime free updates and technical support.
Other similar solutions
Typically in virtualized environment one would look for a solution in hypervisor layer. But this typically means you need to license several hosts and probably equip them with SSD disks. All of this adds up to cost. This cost might not make sense if you only have one or two machines that would benefit from the solution. Here’s where PrimoCache or other similar solutions might help.