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In certain circumstances, heavy user activity may cause Linux Code42 servers to slow or pause backup activity and log the error message "too many open files." This occurs due to open file limits imposed by the Linux operating system. This article explains how to correct this issue by increasing the open file limits for Linux.
Windows is not affected by this issue due to the way it handles open files in memory.
In rare cases, individual Linux user devices with very large backup file selections may also exceed the open files limit. For information about increasing the open files limit on user devices, see Backups Stall Due To Too Many Open Files.
Code42 servers for Linux
Under the hood
Linux imposes a limit on the number of files a process can have open at any one time. More accurately, the operating system imposes a limit on the number of file descriptors a process can have open at any one time, but for the purposes of this article, the difference isn't significant.
The Code42 server may reach this limit if there is too much backup activity happening at one time. It typically manifests itself by preventing users from backing up to the destination. Archive maintenance jobs may also stall.
If the Code42 server reaches the operating system's open file limit, logs from the destination include an error in com_backup42_app.log similar to the one below:
Caused by: java.io.FileNotFoundException: /2tb/backups/358017395638843928/cpbf0000000000000035259/cpbdf (Too many open files)
It's possible for this issue to manifest itself in different error messages, but the messages always contain the string "Too many open files." See Sending Logs To Enterprise Support for more information about working with log files.
The sections below cover how to check and change the open files limit.
Step 1: Check the Code42 server open files limit
To check the open files limit in /proc/[PID]/limits, use the process ID of the Code42 server service.
psto find the process ID:
ps aux | grep proserver
catto view the limit for the process ID:
sudo cat /proc/[PID]/limits
In the following example, the Code42 server service has a PID of 4758 and an open files limit of 1024 (shown in bold text).
code42@ubuntu:~$ ps aux | grep proserver root 4758 67.0 18.2 1554672 187280 pts/2 Sl 09:29 0:03 /opt/proserver/jre/bin/java -Dapp=CPServer -server -Dnetworkaddress.cache.ttl=300 -Djava.net.preferIPv4Stack=true -Ddrools.compiler=JANINO -Dfile.encoding=UTF-8 -Dc42.native.md5.enabled=false -XX:+DisableExplicitGC -XX:+UseAdaptiveGCBoundary -XX:PermSize=256m -XX:MaxPermSize=256m -Xss256k -Xms256m -Xmx1024m -jar /opt/proserver/lib/com.backup42.app.jar -prop conf/conf_proe.properties -config conf/conf_proe.groovy erik 4771 0.0 0.0 7636 920 pts/2 S+ 09:29 0:00 grep --color=auto proserver code42@ubuntu:~$ sudo cat /proc/4758/limits Limit Soft Limit Hard Limit Units Max cpu time unlimited unlimited seconds Max file size unlimited unlimited bytes Max data size unlimited unlimited bytes Max stack size 8388608 unlimited bytes Max core file size 0 unlimited bytes Max resident set unlimited unlimited bytes Max processes unlimited unlimited processes Max open files 1024 1024 files Max locked memory 65536 65536 bytes Max address space unlimited unlimited bytes Max file locks unlimited unlimited locks Max pending signals 16382 16382 signals Max msgqueue size 819200 819200 bytes Max nice priority 20 20 Max realtime priority 0 0 Max realtime timeout unlimited unlimited us
Step 2: Increase the Code42 server open files limit
- Stop the Code42 server service by running the following command:
sudo /opt/proserver/bin/proserver stop
- Open the /opt/proserver/.proserverrc file in a plain text editor.
If this file does not already exist, create it.
- Add the following lines to the file:
# Increase open files limit ulimit -n 409600
- Save the file.
- Run the following command to start the Code42 server service.
sudo /opt/proserver/bin/proserver start