Edge sizing guidelines
The main considerations for sizing your Edge deployment are as follows:
• Disk size—What is the expected capacity of the Edge blockstore?
– Your calculations can be affected depending on if LUNs are pinned, unpinned, or local.
– During WAN outages when the Edge cannot synchronize write operations back through the Core to the LUNs in the data center, the Edge uses a write reserve area on the blockstore to store the data. As described in “Pin the LUN and prepopulate the blockstore,” this area is 10 percent of the blockstore capacity.
• Input/output operations per second (IOPS)—If you are replacing existing storage in the branch office, you can calculate this value from the number and types of drives in the devices you want to replace. Remember that the drives might not have been operating at their full performance capacity. So, if an accurate figure is required, consider using performance monitoring tools that might be included within the server OS: for example, perfmon.exe in Windows.
Other potentially decisive factors:
• HA requirements (PSU, disk, network redundancy)
• CPU and memory requirements
• WAN optimization requirements (bandwidth and connection count)
See the Edge specification sheets for capacity and capabilities of each model.
When sizing the Edge appliance, you have the additional flexibility of choosing optimized WAN bandwidth needed after you have completed sizing for disk size, IOPS, and CPU. For more information, see
Rdisk traffic routing options.