The overall system uptime can be seen in the dashboard widget or from the uptime command.
The Firepower server processes will generate some (many) log messages when they start. You can see them in the syslog or parse them in /var/log/ directory, messages file, as shown in some examples below:
admin@fmc:/var/log$ cat messages | grep "Started SF" Dec 12 12:10:29 fmc SF-IMS[4247]: [4247] pm:process [INFO] Started SFDCNotificationd (29403) Dec 12 12:10:30 fmc SF-IMS[4247]: [4247] pm:process [INFO] Started SFRemediateD (29465) Dec 12 12:11:00 fmc SF-IMS[4247]: [4247] pm:process [INFO] Started SFNotificationd (29854) Dec 12 12:11:33 fmc SF-IMS[4247]: [4247] pm:process [INFO] Started SFTop10Cacher (30199) Dec 12 12:11:33 fmc SF-IMS[4247]: [4247] pm:process [INFO] Started SFDataCorrelator (30203)
admin@fmc:/var/log$ cat messages | grep http Dec 12 12:08:41 fmc SF-IMS[4247]: [4247] pm:process [INFO] Stopping httpsd Dec 12 12:09:41 fmc SF-IMS[4247]: [4247] pm:log [INFO] Process 'httpsd' closed output. Dec 12 12:09:42 fmc SF-IMS[4247]: [4247] pm:CGroups [INFO] Apply: defaulting memory cgroup to System for httpsd. Dec 12 12:09:42 fmc SF-IMS[4247]: [4247] pm:process [INFO] Adding process: httpsd Dec 12 12:10:29 fmc SF-IMS[4247]: [4247] pm:process [INFO] Started httpsd (29407) Dec 12 12:10:29 fmc SF-IMS[29407]: [29407] pm:CGroups [INFO] Apply: process <p29407/httpsd>. Dec 12 12:12:19 fmc SF-IMS[30203]: [30203] SFDataCorrelator:FileExtractCloud [INFO] host: https://panacea.threatgrid.com Dec 12 12:12:19 fmc SF-IMS[29860]: [31425] ADI:adi.ISEConnection [INFO] Captured Jabberwerx log:2017-12-12T12:12:19 [ INFO]: curl_easy_setopt() for CURLOPT_URL: 'https://ise-new.ccielab.mrneteng.com:8910/pxgrid/mnt/sd/getSessionListByTime' admin@fmc:/var/log$
A similar set of messages are generated on the sensor side and you can find them in the same directory there.
