With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
csfUpgradeFlashSize
csf Upgrade Flash Size
1.3.6.1.4.1.9.10.45.1.1.2
The size of available FLASH memory in the system, in kilobytes. For example: 128 equals 131072 bytes (128 bytes times 1024).
Back to CISCO-SIBU-FLASH-MIB MIB page.
IPHost Network monitor allows you to monitor csfUpgradeFlashSize on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco mobile switches right now.