Linux资源限制配置文件是/etc/security/limits.conf。限制用户可使用的资源数量对系统的稳定性非常重要。您可以通过调整资源限制数量改进系统性能。limits.conf文件如下所示：
# /etc/security/limits.conf
#
#This file sets the resource limits for the users logged in via PAM.
#It does not affect resource limits of the system services.
#
#Also note that configuration files in /etc/security/limits.d directory,
#which are read in alphabetical order, override the settings in this
#file in case the domain is the same or more specific.
#That means, for example, that setting a limit for wildcard domain here
#can be overridden with a wildcard setting in a config file in the
#subdirectory, but a user specific setting here can be overridden only
#with a user specific setting in the subdirectory.
#
#Each line describes a limit for a user in the form:
#
#<domain> <type> <item> <value>
#
#Where:
#<domain> can be:
# - a user name
# - a group name, with @group syntax
# - the wildcard *, for default entry
# - the wildcard %, can be also used with %group syntax,
# for maxlogin limit
#
#<type> can have the two values:
# - "soft" for enforcing the soft limits
# - "hard" for enforcing hard limits
#
#<item> can be one of the following:
# - core - limits the core file size (KB)
# - data - max data size (KB)
# - fsize - maximum filesize (KB)
# - memlock - max locked-in-memory address space (KB)
# - nofile - max number of open file descriptors
# - rss - max resident set size (KB)
# - stack - max stack size (KB)
# - cpu - max CPU time (MIN)
# - nproc - max number of processes
# - as - address space limit (KB)
# - maxlogins - max number of logins for this user
# - maxsyslogins - max number of logins on the system
# - priority - the priority to run user process with
# - locks - max number of file locks the user can hold
# - sigpending - max number of pending signals
# - msgqueue - max memory used by POSIX message queues (bytes)
# - nice - max nice priority allowed to raise to values: [-20, 19]
# - rtprio - max realtime priority
#
#<domain> <type> <item> <value>
#
#* soft core 0
#* hard rss 10000
#@student hard nproc 20
#@faculty soft nproc 20
#@faculty hard nproc 50
#ftp hard nproc 0
#@student - maxlogins 4
# End of file
其中soft是一个警告值，hard是真正意义的阈值，超过系统就会报错，一般情况下两者设为同一个值。一般保持系统安装时的默认值即可。可配置的资源有如下种类：
nofile、noproc、core参数可修改为如下值：
# *表示所有用户，可只设置root和特定用户
* soft nofile 65536
# 注意：设置nofile的hard limit不能大于/proc/sys/fs/nr_open，否则注销后将无法正常登陆
* hard nofile 65535
* soft nproc 65536
* hard nproc 65535
# unlimited表示无限制
* soft core unlimited
* hard core unlimited