在升级完FPR2100 防火墙后，显示系统升级成功，
出现以下报错信息，
Sensor table is unavailable. Mysql is down, or DB install did not complete sucessfully. Retry: 52 MaxRetries: 60 Error: Cannot connect to DB at /usr/local/sf/lib/perl/5.24.4/SF/SFDBI.pm line 750.
Sensor table is unavailable. Mysql is down, or DB install did not complete sucessfully. Retry: 53 MaxRetries: 60 Error: Cannot connect to DB at /usr/local/sf/lib/perl/5.24.4/SF/SFDBI.pm line 750.
DB currently is not available, S19cert-tun-init executing might fail
出现以上信息后，可执行下图命令，
可参考以下Cisco官方解决手册的链接。
https://www.cisco.com/c/zh_cn/td/docs/security/firepower/2100/troubleshoot_fxos/b_2100_CLI_Troubleshoot/b_2100_CLI_Troubleshoot_chapter_011.html#task_uzp_kv1_hbb