The disk space usage in the opt_cisco_config mount point of the Firepower eXtensible Operating System (FXOS) is increasing:
asa# connect asa
firepower-1210CE# scope fabric-interconnect
firepower-1210CE /fabric-interconnect # show storage
Storage on local flash drive of fabric interconnect:
Mount Point Size (MBytes) Used Percentage
------------------------ ---------------- ---------------
mnt_boot 7428 23
opt_cisco_config 921 55 <--------
opt_cisco_csp 352685 2
opt_cisco_platform_logs 921 4
usbdrive Nothing Empty
var_data_cores 37243 Empty
The file system mounted at the opt_cisco_config mount point has 921 MB of total disk space, and 55% of disk space usage.
According to the FXOS troubleshoot file, /opt/cisco/config/var/log/process_stdout.log is the largest file consuming more than 400 megabytes of disk space:
$ cd opt/cisco/config/var/log
opt/cisco/config/var/log$ ls -lSsgho
total 435M
432M -rwxrwxrwx 1 432M May 21 07:57 process_stdout.log
2.3M -rwxrwxrwx 1 2.3M May 21 07:57 cron
292K -rwxrwxrwx 1 290K May 21 07:57 lastlog
232K -rwxrwxrwx 1 229K May 21 07:56 ASAconsole.log
72K -rwxrwxrwx 1 69K May 21 07:56 dmesg
64K -rwxrwxrwx 1 61K May 21 07:57 wtmp-20260227
32K -rwxrwxrwx 1 32K May 21 07:56 faillog
20K -rwxrwxrwx 1 18K May 21 07:56 wtmp
0 drwxrwxrwx 1 4.0K May 21 07:57 sa
4.0K -rwxrwxrwx 1 2.4K May 21 07:56 btmp-20260227
4.0K -rwxrwxrwx 1 1.6K May 21 07:56 btmp
0 -rwxrwxrwx 1 160 May 21 07:56 postinstall.log
0 -rwxrwxrwx 1 0 May 21 07:57 boot
0 -rwxrwxrwx 1 0 May 21 07:57 process_stderr.log
Additionally, the size of the file increases day by day and the file is never rotated or compressed.
Secure Firewall 1210, 1220 and 1230 running ASA software. Other platforms can also be affected.
ASA version 9.22(2)32. Other software versions can also be affected.
Contact TAC to apply the workaround for the Cisco bug ID CSCwu45359. The workaround requires backend CLI access and involves manually truncating the largest log files inside the /opt/cisco/config/var/log directory.
Excessive disk space usage by file /opt/cisco/config/var/log/process_stdout.log is caused by continuous loggingof these messages once a minute:
2026-05-20 10:25:07 dnsproxy[33143]: -p <port> UDP port nunber to listen on. Default: 53
2026-05-20 10:25:07 dnsproxy[33143]: -k Use NLP addressing. Default: use addressing
2026-05-20 10:25:09 monit[27882]: 'statserver' process is running with pid 31449
2026-05-20 10:26:07 dnsproxy[36667]: Unknown option/asa/bin/dnsproxy usage:
2026-05-20 10:26:07 dnsproxy[36667]: -h Print this help and terminate
2026-05-20 10:26:07 dnsproxy[36667]: -c <file> read DNS server info from file. Default: /etc/sf/dnsproxy.conf
2026-05-20 10:26:07 dnsproxy[36667]: -d <level> debug level. Default: 3
2026-05-20 10:26:07 dnsproxy[36667]: -i <IP> IPv4 address to listen on. Default: 127.0.0.1
2026-05-20 10:26:07 dnsproxy[36667]: -p <port> UDP port nunber to listen on. Default: 53
2026-05-20 10:26:07 dnsproxy[36667]: -k Use NLP addressing. Default: use addressing
..
2026-05-20 10:27:07 dnsproxy[39999]: Unknown option/asa/bin/dnsproxy usage:
2026-05-20 10:27:07 dnsproxy[39999]: -h Print this help and terminate
2026-05-20 10:27:07 dnsproxy[39999]: -c <file> read DNS server info from file. Default: /etc/sf/dnsproxy.conf
2026-05-20 10:27:07 dnsproxy[39999]: -d <level> debug level. Default: 3
2026-05-20 10:27:07 dnsproxy[39999]: -i <IP> IPv4 address to listen on. Default: 127.0.0.1
2026-05-20 10:27:07 dnsproxy[39999]: -p <port> UDP port nunber to listen on. Default: 53
2026-05-20 10:27:07 dnsproxy[39999]: -k Use NLP addressing. Default: use addressing
This excessive logging is tracked under Cisco bug ID CSCwu45359. Additionally, as part of the internal lab reproduction, it is confirmed that the file /opt/cisco/config/var/log/process_stdout.log is never rotated and compressed. The lack of rotation is tracked under Cisco bug ID CSCwu45848.
Cisco bug ID CSCwu45359
Cisco bug ID CSCwu45848
| Revision | Publish Date | Comments |
|---|---|---|
1.0 |
21-May-2026
|
Initial Release |