I picked up a Cisco SRE-900 module off eBay a while ago to try out the WLC and SRE-V (VMWare ESXi) software. This module plugs into an ISR G2 router’s SM slot. It comes with a 1.8Ghz processor and 4GB of RAM, plenty to run the WLC (overkill really) or OK to run ESXi.
After seeing the potential for ESXi on it, I picked up an SRE-300 for the WLC software and dedicated the SRE-900 for ESXi. The issue I hit was that the RAM it came with was very limiting on how many VMs I could run. I googled around to see if anyone else had upgraded their system with generic RAM (the Cisco part numbers were extremely expensive) but couldn’t find any examples. With this in mind I wanted to keep the cost low in case the system rejected the RAM I purchased. So I picked up 2 4GB DDR2 PC-5300 VLP modules off eBay for ~$50 together.
The generic modules went into the SRE-900 without issue and when I booted it up in the router it confirmed that it was all accounted for:
DDR Memory 8192 MB detected Intel(R) Core(TM)2 Duo CPU L9400 @ 1.86GHz BIOS SM 3.52.8, BIOS Build date: 02/08/2011 Intel(R) Core(TM)2 Duo CPU L9400 @ 1.86GHz BIOS SM 3.52.8, BIOS Build date: 02/08/2011 System now booting...
Next up… 16GB of RAM. Well, if the processor/storage don’t become the bottlenecks as I deploy more VMs.