when i use the pm2, The log4js log segmentation is not work?

my log4j config is:
```module.exports = {
appenders: {
console: { type: 'console' },
out: {
type: 'file',
filename: './logs/out.log',
maxLogSize: 10 * 1024,
layout: {
type: 'basic'
},
backups: 5,
},
error: {
type: 'file',
filename: './logs/error.log',
maxLogSize: 10 * 1024,
layout: {
type: 'basic'
},
backups: 5,
},
zk: {
type: 'file',
filename: './logs/zk.log',
// 1M 单文件大小，单位字节
maxLogSize: 10 * 1024 * 1024,
backups: 5
},
monitor: {
type: 'file',
filename: './logs/monitor.log',
// 1M 单文件大小，单位字节
maxLogSize: 10 * 1024 * 1024,
backups: 5
},
cron: {
type: 'dateFile',
filename: './logs/cron.log',
pattern: '-yyyy-MM-dd.log',
},
},
categories: {
default: { appenders: ['console', 'out'], level: 'info' },
error: { appenders: ['error'], level: 'error' },
zk: { appenders: ['zk'], level: 'info' },
monitor: { appenders: ['monitor'], level: 'info' },
cron: { appenders: ['cron'], level: 'info' },
}
};
```

and the pm2 config is:

```{
"apps": [
{
"name": "api-server",
"script": "src/app.js",
"max_memory_restart": "1G",
"error_file" : "./logs/error.log",
"out_file" : "./logs/out.log",
// "out_file": "/dev/null",
// "error_file": "/dev/null",
"merge_logs" : true,
"log_date_format" : "YYYY-MM-DD HH:mm Z",
"env": {
"NODE_ENV": "development"
},
"env_test" : {
"NODE_ENV": "test"
},
"env_pro" : {
"NODE_ENV": "production"
}
},
{
"name": "cron-server",
"script": "src/cron.js",
"max_memory_restart": "1G",
"error_file" : "./logs/error.log",
"out_file" : "./logs/out.log",
"merge_logs" : true,
"log_date_format" : "YYYY-MM-DD HH:mm Z",
"env": {
"NODE_ENV": "development"
},
"env_test" : {
"NODE_ENV": "test"
},
"env_pro" : {
"NODE_ENV": "production"
}
}
]
}
```

But the error.log log segmentation is not work! what should i do?
node 6.9.11
pm2 2.6.1
log4js 2.3.11

thanks for first!

The issue names only the log4js and PM2 configuration snippets, with Node.js 6.9.11, PM2 2.6.1, and log4js 2.3.11; no repository files or tests are provided. Reproduce the error.log rotation behavior with these versions, then determine whether the failure is in the log4js file appender or PM2's error_file handling and document a verified resolution.

Written by the indexing model from the issue text.