在項目實際使用過程中，客戶反饋能打開網頁但無法登陸，第一時間感覺到應該是數據庫服務器掛了，于是查看Mongodb數據庫服務器日志，果不其然掛了。
報錯信息如下：

2020-12-28T13:21:21.731+0800 E STORAGE  [conn2624] WiredTiger error (24) [1609132881:731422][23581:0x7fe157189700], WT_SESSION.create: __posix_directory_sync, 135: /data1/mongodb/data/db/: directory-sync: open: Too many open files Raw: [1609132881:731422][23581:0x7fe157189700], WT_SESSION.create: __posix_directory_sync, 135: /data1/mongodb/data/db/: directory-sync: open: Too many open files
2020-12-28T13:21:21.731+0800 E STORAGE  [conn2624] WiredTiger error (24) [1609132881:731616][23581:0x7fe157189700], WT_SESSION.create: __posix_directory_sync, 151: /data1/mongodb/data/db/collection-1063-1706476241051221735.wt: directory-sync: Too many open files Raw: [1609132881:731616][23581:0x7fe157189700], WT_SESSION.create: __posix_directory_sync, 151: /data1/mongodb/data/db/collection-1063-1706476241051221735.wt: directory-sync: Too many open files
2020-12-28T13:21:21.731+0800 E STORAGE  [conn2624] WiredTiger error (-31804) [1609132881:731651][23581:0x7fe157189700], WT_SESSION.create: __wt_panic, 494: the process must exit and restart: WT_PANIC: WiredTiger library panic Raw: [1609132881:731651][23581:0x7fe157189700], WT_SESSION.create: __wt_panic, 494: the process must exit and restart: WT_PANIC: WiredTiger library panic
2020-12-28T13:21:21.731+0800 F –        [conn2624] Fatal Assertion 50853 at src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp 420
2020-12-28T13:21:21.731+0800 F –        [conn2624]

***aborting after fassert() failure

可以看到核心問題就是 Too many open files。經查閱相關資料，造成如下問題的原因就是Centos7給每個用戶默認的同時打開文件的數值為1024，可通過如下配置文件查看：

ulimit -a

其中所有的參數均可修改，那么如何修改open files呢？
在此提供兩種方法：
首先查看系統全局參數：

所以我們可以修改的最大值也是174198

具體修改方法一：
新建一個nofile.conf文件：

vi /etc/security/limits.d/nofile.conf