Some buddy of mine is using PVS in a university to manage the students PC. They are serving the images out of raid mirrors of Intel DC S3500 SSDs to reduce the number of spindles installed on the Citrix PVS servers. It’s a cost efficient solution and since they don’t need to host the write cache, read optimised SSDs are best suited for this task.
Over time more and more images have been created for serving different hardware and use cases totaling about 650 GB of used space on the SSD mirrors. Space started to run low so they decided to enable deduplication on the 2012 R2 PVS servers. Since there is almost no write activity on the disks, fear of write amplification caused by deduplication is not a real issue. The VDI optimised dedup was chosen even if there is no write activity, but due to the similarity of workloads and due to the fact that this way it’s possible to deduplicate also open files. No background deduplication is taking place and there is a single dedup schedule taking place during the night when images are usually not served.
Space usage went down from 650 GB to 77 GB, impressive but expected, PVS images have great similarity also across different operating system versions. This setup is now in test phase and if no issues arise, deduplication will also be deployed in the remaining PVS servers.
