Viewing Logs

Examine the Memory Machine log files to troubleshoot errors – for example, to determine why a license didn't load.

About this task

The file path of the Memory Machine logs is configured in the Memory Machine configuration file, mvmalloc.yml. If the configuration has not been changed from the default, the log files are located in /var/log/memverge.

Note: You can change the malloc_log file location for any application instance by starting the instance with a configuration file that specifies a new location. Unless there is a compelling reason to do otherwise, MemVerge recommends that you log all instances to the same location to avoid confusion.

Procedure

List the log file directory. For example:
```
# ls -l /var/log/memverge/
...
-rwxrwx--- 1 mvmm mvmm      488 Sep  6 10:34 malloc_log_redis-server_10902_1630949650
-rwxrwx--- 1 mvmm mvmm 10485740 Sep  1 09:51 mmagent-2021-09-01T09-51-51.001.log
-rw-r--r-- 1 mvmm mvmm    22296 Sep  8 16:34 mmagent.log
-rwxrwx--- 1 mvmm mvmm 10485741 Aug 30 05:25 mmctl-2021-08-30T05-25-11.001.log
-rw-r--r-- 1 mvmm mvmm    72488 Sep  8 17:15 mmctl.log
-rwxrwx--- 1 mvmm mvmm      123 Sep  7 16:15 mvcsnapd_log
-rwxrwx--- 1 mvmm mvmm      347 Sep  7 16:15 mvmallocd_log
-rwxrwx--- 1 mvmm mvmm  2215931 Sep  8 17:16 mvsvcd_log
-rwxrwx--- 1 mvmm mvmm    45920 Sep  8 my-app-snap_tmux_my-app-tmux_2021-08-30T03-11-09.log
```
where:

malloc_log

is the MemVerge TMS log prefix for application logs.

mmagent.log

is the log for the Memory Machine Agent process that communicates with the management server.

mmctl.log

is the log for the Memory Machine Management Service.

mvcsnapd_log

is the log for the Memory Machine cluster snapshot and snapshot replication service.

mvmallocd_log

is the MVMAS information log.

mvsvcd_log

is the log for the Memory Machine Services Daemon service.

my_app_tmux_my-app-snap_tmux_timestamp.log

is the tmux log for an application instance with snapshot label my-app-snap and tmux session name my-app-tmux.

Note: Memory Machine logs "roll over" when the file size reaches about 10 MB. The existing log is renamed with a datestamp and a new log is created. The files mmagent-2021-09-01T09-51-51.001.log and mmctl-2021-08-30T05-25-11.001.log in the example are rollover logs.

View an individual logfile using a text editor or command-line utility. For example:

# less /var/log/memverge/mvmallocd_log
-----NEW MVMLOG FILE 2020-05-27 14:46:39
License loaded successfully.
Startup: NO_ERROR
Chunk Usage: (187 / 64508)
dax device capacity 135283081216, less than license allowed capacity 8796093022208, set capacity limit to 135283081216
Open /var/log/memverge/mvmallocd.evt.1590615999.38927ae4: NO_ERROR
service starting
Unlock mem-elIAAMbhwV7z8vPITVL+Sw==: DPME_NO_ERROR
...

The /var/log/messages file contains OS level messages that may also help in troubleshooting.
View the messages log:
```
# ls /var/log/messages
-rw-------. 1 root root 458623 Mar 12 13:12 /var/log/messages
```
View individual application instance log files. The name of an instance logfile depends on the logging parameter used in the application configuration file, mvmalloc.yml:
If the LogNamePrefix parameter is used, each instance writes to its own log file named as follows:
```
prefix_command_pid_timestamp
```
where

prefix

is the logfile prefix assigned to the LogNamePrefix parameter

command

is the command-line name of the application

pid

is the process ID of the instance

timestamp

represents the time that the process was started

If the LogName parameter is used, all processes that use that application configuration file write to the file path specified in the parameter.