This read-only Gauge32 field is the 'memAvailable' property of the 'FexSystemStats' managed object in Cisco UCS Manager's equipment-inventory schema reporting the memory currently available (free plus reclaimable cache) on the FEX's onboard OS. This is a more realistic measure of usable memory than raw free memory alone, since it counts cache that the OS can reclaim on demand, so a healthy FEX can show low KernelMemFree but still have plenty of MemAvailable. A FEX showing only 20MB KernelMemFree but 90MB MemAvailable is not actually under memory pressure, most of its memory is just being used productively for cache.