这里是/proc/meminfo：
MemTotal: 7629488 kB
MemFree: 237528 kB
Buffers: 70536 kB
Cached: 45612 kB
SwapCached: 0 kB
Active: 99400 kB
Inactive: 86340 kB
Active(anon): 69608 kB
Inactive(anon): 208 kB
Active(file): 29792 kB
Inactive(file): 86132 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 44 kB
Writeback: 0 kB
AnonPages: 69508 kB
Mapped: 7212 kB
Shmem: 224 kB
Slab: 7098800 kB
SReclaimable: 15452 kB
SUnreclaim: 7083348 kB
KernelStack: 1032 kB
PageTables: 4720 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 3814744 kB
Committed_AS: 176296 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 26116 kB
VmallocChunk: 34359710188 kB
HardwareCorrupted: 0 kB
AnonHugePages: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 7872512 kB
DirectMap2M: 0 kB
free -m显示如下：
total used free shared buffers cached
Mem: 7450 7219 231 0 69 44
-/+ buffers/cache: 7105 345
Swap: 0 0 0
htop以下是按内存消耗排序的前几行：
1 [ 0.0%] Tasks: 75, 8 thr; 1 running
2 [| 0.7%] Load average: 0.08 0.03 0.05
Mem[|||||||||||||||||||||||||||||||||||||||||||||||||||7115/7450MB] Uptime: 1 day, 07:44:49
Swp[ 0/0MB]
PID USER PRI NI VIRT RES SHR S CPU% MEM% TIME+ Command
983 redis 20 0 35324 26288 728 S 0.0 0.3 12:12.70 /usr/bin/redis-server /etc/redis/redis.conf
10152 bharadwaj 20 0 21760 4344 1760 S 0.0 0.1 0:00.21 bash -i
10923 bharadwaj 20 0 21748 4316 1748 S 0.0 0.1 0:00.24 bash -i
9931 bharadwaj 20 0 21704 4240 1716 S 0.0 0.1 0:00.14 bash -i
11278 bharadwaj 20 0 21704 4236 1712 S 0.0 0.1 0:00.14 bash -i
11689 bharadwaj 20 0 21704 4236 1712 S 0.0 0.1 0:00.13 bash -i
10917 bharadwaj 20 0 21704 4232 1712 S 0.0 0.1 0:00.20 bash -i
9873 bharadwaj 20 0 21704 4132 1612 S 0.0 0.1 0:00.14 -bash
10094 bharadwaj 20 0 21704 4128 1612 S 0.0 0.1 0:00.14 -bash
10744 bharadwaj 20 0 21704 4128 1612 S 0.0 0.1 0:00.24 -bash
10745 bharadwaj 20 0 21704 4128 1612 S 0.0 0.1 0:00.22 -bash
11220 bharadwaj 20 0 21704 4124 1612 S 0.0 0.1 0:00.14 -bash
11631 bharadwaj 20 0 21704 4124 1612 S 0.0 0.1 0:00.14 -bash
9997 root 20 0 73432 3648 2840 S 0.0 0.0 0:00.01 sshd: bharadwaj [priv]
10454 root 20 0 73432 3648 2840 S 0.0 0.0 0:00.01 sshd: bharadwaj [priv]
10452 root 20 0 73432 3644 2840 S 0.0 0.0 0:00.01 sshd: bharadwaj [priv]
11123 root 20 0 73432 3644 2840 S 0.0 0.0 0:00.01 sshd: bharadwaj [priv]
11490 root 20 0 73432 3644 2840 S 0.0 0.0 0:00.00 sshd: bharadwaj [priv]
9771 root 20 0 73432 3640 2840 S 0.0 0.0 0:00.01 sshd: bharadwaj [priv]
681 root 20 0 50036 2940 2332 S 0.0 0.0 0:02.37 /usr/sbin/sshd -D
11487 postfix 20 0 44308 2604 2040 S 0.0 0.0 0:00.00 smtp -t unix -u -c
11489 postfix 20 0 27416 2304 1780 S 0.0 0.0 0:00.00 local -t unix
如果有帮助的话，以下是redis-cli信息：
redis 127.0.0.1:6379> info
redis_version:2.2.12
redis_git_sha1:00000000
redis_git_dirty:0
arch_bits:64
multiplexing_api:epoll
process_id:983
uptime_in_seconds:113910
uptime_in_days:1
lru_clock:1825976
used_cpu_sys:186.84
used_cpu_user:545.43
used_cpu_sys_children:35.02
used_cpu_user_children:13.96
connected_clients:1
connected_slaves:0
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:0
used_memory:23849056
used_memory_human:22.74M
used_memory_rss:26918912
mem_fragmentation_ratio:1.13
use_tcmalloc:0
loading:0
aof_enabled:0
changes_since_last_save:0
bgsave_in_progress:0
last_save_time:1423351594
bgrewriteaof_in_progress:0
total_connections_received:232605
total_commands_processed:20342906
expired_keys:6180
evicted_keys:0
keyspace_hits:19789182
keyspace_misses:276593
hash_max_zipmap_entries:512
hash_max_zipmap_value:64
pubsub_channels:0
pubsub_patterns:0
vm_enabled:0
role:master
db0:keys=4310,expires=79
有一个类似问题之前问过，但这些答案都对情况没有帮助。清除缓存或缓冲区没有帮助，因为它们总共消耗了大约 100 MB。此外，将 redis maxmemory 选项更改为其内存优化页面对情况没有帮助。每次内存使用率达到 99% 左右时，都需要重新启动服务器，这时 redis 就会崩溃。
如何解决这种情况？我可能遗漏了一些基本内容。欢迎提出任何建议！
编辑：这是redis.conf文件：
# Redis configuration file example
# Note on units: when memory size is needed, it is possible to specifiy
# it in the usual form of 1k 5GB 4M and so forth:
#
# 1k => 1000 bytes
# 1kb => 1024 bytes
# 1m => 1000000 bytes
# 1mb => 1024*1024 bytes
# 1g => 1000000000 bytes
# 1gb => 1024*1024*1024 bytes
#
# units are case insensitive so 1GB 1Gb 1gB are all the same.
# By default Redis does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
daemonize yes
# When running daemonized, Redis writes a pid file in /var/run/redis.pid by
# default. You can specify a custom pid file location here.
pidfile /var/run/redis/redis-server.pid
# Accept connections on the specified port, default is 6379.
# If port 0 is specified Redis will not listen on a TCP socket.
port 6379
# If you want you can bind a single interface, if the bind option is not
# specified all the interfaces will listen for incoming connections.
#
#bind 127.0.0.1
# Specify the path for the unix socket that will be used to listen for
# incoming connections. There is no default, so Redis will not listen
# on a unix socket when not specified.
#
# unixsocket /var/run/redis/redis.sock
# Close the connection after a client is idle for N seconds (0 to disable)
timeout 300
# Set server verbosity to 'debug'
# it can be one of:
# debug (a lot of information, useful for development/testing)
# verbose (many rarely useful info, but not a mess like the debug level)
# notice (moderately verbose, what you want in production probably)
# warning (only very important / critical messages are logged)
loglevel notice
# Specify the log file name. Also 'stdout' can be used to force
# Redis to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile /var/log/redis/redis-server-2feb15.log
# To enable logging to the system logger, just set 'syslog-enabled' to yes,
# and optionally update the other syslog parameters to suit your needs.
# syslog-enabled no
# Specify the syslog identity.
# syslog-ident redis
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# syslog-facility local0
# Set the number of databases. The default database is DB 0, you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
databases 16
################################ SNAPSHOTTING #################################
#
# Save the DB on disk:
#
# save <seconds> <changes>
#
# Will save the DB if both the given number of seconds and the given
# number of write operations against the DB occurred.
#
# In the example below the behaviour will be to save:
# after 900 sec (15 min) if at least 1 key changed
# after 300 sec (5 min) if at least 10 keys changed
# after 60 sec if at least 10000 keys changed
#
# Note: you can disable saving at all commenting all the "save" lines.
save 900 1
save 300 10
save 60 10000
# Compress string objects using LZF when dump .rdb databases?
# For default that's set to 'yes' as it's almost always a win.
# If you want to save some CPU in the saving child set it to 'no' but
# the dataset will likely be bigger if you have compressible values or keys.
rdbcompression yes
# The filename where to dump the DB
dbfilename dump.rdb
# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# Also the Append Only File will be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
dir /var/lib/redis
################################# REPLICATION #################################
# Master-Slave replication. Use slaveof to make a Redis instance a copy of
# another Redis server. Note that the configuration is local to the slave
# so for example it is possible to configure the slave to save the DB with a
# different interval, or to listen to another port, and so on.
#
# slaveof <masterip> <masterport>
# If the master is password protected (using the "requirepass" configuration
# directive below) it is possible to tell the slave to authenticate before
# starting the replication synchronization process, otherwise the master will
# refuse the slave request.
#
# masterauth <master-password>
# When a slave lost the connection with the master, or when the replication
# is still in progress, the slave can act in two different ways:
#
# 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will
# still reply to client requests, possibly with out of data data, or the
# data set may just be empty if this is the first synchronization.
#
# 2) if slave-serve-stale data is set to 'no' the slave will reply with
# an error "SYNC with master in progress" to all the kind of commands
# but to INFO and SLAVEOF.
#
slave-serve-stale-data yes
################################## SECURITY ###################################
# Require clients to issue AUTH <PASSWORD> before processing any other
# commands. This might be useful in environments in which you do not trust
# others with access to the host running redis-server.
#
# This should stay commented out for backward compatibility and because most
# people do not need auth (e.g. they run their own servers).
#
# Warning: since Redis is pretty fast an outside user can try up to
# 150k passwords per second against a good box. This means that you should
# use a very strong password otherwise it will be very easy to break.
#
# requirepass foobared
# Command renaming.
#
# It is possilbe to change the name of dangerous commands in a shared
# environment. For instance the CONFIG command may be renamed into something
# of hard to guess so that it will be still available for internal-use
# tools but not available for general clients.
#
# Example:
#
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#
# It is also possilbe to completely kill a command renaming it into
# an empty string:
#
# rename-command CONFIG ""
################################### LIMITS ####################################
# Set the max number of connected clients at the same time. By default there
# is no limit, and it's up to the number of file descriptors the Redis process
# is able to open. The special value '0' means no limits.
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#
# maxclients 128
# Don't use more memory than the specified amount of bytes.
# When the memory limit is reached Redis will try to remove keys with an
# EXPIRE set. It will try to start freeing keys that are going to expire
# in little time and preserve keys with a longer time to live.
# Redis will also try to remove objects from free lists if possible.
#
# If all this fails, Redis will start to reply with errors to commands
# that will use more memory, like SET, LPUSH, and so on, and will continue
# to reply to most read-only commands like GET.
#
# WARNING: maxmemory can be a good idea mainly if you want to use Redis as a
# 'state' server or cache, not as a real DB. When Redis is used as a real
# database the memory usage will grow over the weeks, it will be obvious if
# it is going to use too much memory in the long run, and you'll have the time
# to upgrade. With maxmemory after the limit is reached you'll start to get
# errors for write operations, and this may even lead to DB inconsistency.
#
# maxmemory <bytes>
maxmemory 524288000
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached? You can select among five behavior:
#
# volatile-lru -> remove the key with an expire set using an LRU algorithm
# allkeys-lru -> remove any key accordingly to the LRU algorithm
# volatile-random -> remove a random key with an expire set
# allkeys->random -> remove a random key, any key
# volatile-ttl -> remove the key with the nearest expire time (minor TTL)
# noeviction -> don't expire at all, just return an error on write operations
#
# Note: with all the kind of policies, Redis will return an error on write
# operations, when there are not suitable keys for eviction.
#
# At the date of writing this commands are: set setnx setex append
# incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
# sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
# zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
# getset mset msetnx exec sort
#
# The default is:
#
# maxmemory-policy volatile-lru
maxmemory-policy allkeys-lru
# LRU and minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can select as well the sample
# size to check. For instance for default Redis will check three keys and
# pick the one that was used less recently, you can change the sample size
# using the following configuration directive.
#
# maxmemory-samples 3
maxmemory-samples 3
############################## APPEND ONLY MODE ###############################
# By default Redis asynchronously dumps the dataset on disk. If you can live
# with the idea that the latest records will be lost if something like a crash
# happens this is the preferred way to run Redis. If instead you care a lot
# about your data and don't want to that a single record can get lost you should
# enable the append only mode: when this mode is enabled Redis will append
# every write operation received in the file appendonly.aof. This file will
# be read on startup in order to rebuild the full dataset in memory.
#
# Note that you can have both the async dumps and the append only file if you
# like (you have to comment the "save" statements above to disable the dumps).
# Still if append only mode is enabled Redis will load the data from the
# log file at startup ignoring the dump.rdb file.
#
# IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append
# log file in background when it gets too big.
appendonly no
# The name of the append only file (default: "appendonly.aof")
# appendfilename appendonly.aof
# The fsync() call tells the Operating System to actually write data on disk
# instead to wait for more data in the output buffer. Some OS will really flush
# data on disk, some other OS will just try to do it ASAP.
#
# Redis supports three different modes:
#
# no: don't fsync, just let the OS flush the data when it wants. Faster.
# always: fsync after every write to the append only log . Slow, Safest.
# everysec: fsync only if one second passed since the last fsync. Compromise.
#
# The default is "everysec" that's usually the right compromise between
# speed and data safety. It's up to you to understand if you can relax this to
# "no" that will will let the operating system flush the output buffer when
# it wants, for better performances (but if you can live with the idea of
# some data loss consider the default persistence mode that's snapshotting),
# or on the contrary, use "always" that's very slow but a bit safer than
# everysec.
#
# If unsure, use "everysec".
# appendfsync always
appendfsync everysec
# appendfsync no
# When the AOF fsync policy is set to always or everysec, and a background
# saving process (a background save or AOF log background rewriting) is
# performing a lot of I/O against the disk, in some Linux configurations
# Redis may block too long on the fsync() call. Note that there is no fix for
# this currently, as even performing fsync in a different thread will block
# our synchronous write(2) call.
#
# In order to mitigate this problem it's possible to use the following option
# that will prevent fsync() from being called in the main process while a
# BGSAVE or BGREWRITEAOF is in progress.
#
# This means that while another child is saving the durability of Redis is
# the same as "appendfsync none", that in pratical terms means that it is
# possible to lost up to 30 seconds of log in the worst scenario (with the
# default Linux settings).
#
# If you have latency problems turn this to "yes". Otherwise leave it as
# "no" that is the safest pick from the point of view of durability.
no-appendfsync-on-rewrite no
################################ VIRTUAL MEMORY ###############################
# Virtual Memory allows Redis to work with datasets bigger than the actual
# amount of RAM needed to hold the whole dataset in memory.
# In order to do so very used keys are taken in memory while the other keys
# are swapped into a swap file, similarly to what operating systems do
# with memory pages.
#
# To enable VM just set 'vm-enabled' to yes, and set the following three
# VM parameters accordingly to your needs.
vm-enabled no
# vm-enabled yes
# This is the path of the Redis swap file. As you can guess, swap files
# can't be shared by different Redis instances, so make sure to use a swap
# file for every redis process you are running. Redis will complain if the
# swap file is already in use.
#
# The best kind of storage for the Redis swap file (that's accessed at random)
# is a Solid State Disk (SSD).
#
# *** WARNING *** if you are using a shared hosting the default of putting
# the swap file under /tmp is not secure. Create a dir with access granted
# only to Redis user and configure Redis to create the swap file there.
vm-swap-file /var/lib/redis/redis.swap
# vm-max-memory configures the VM to use at max the specified amount of
# RAM. Everything that deos not fit will be swapped on disk *if* possible, that
# is, if there is still enough contiguous space in the swap file.
#
# With vm-max-memory 0 the system will swap everything it can. Not a good
# default, just specify the max amount of RAM you can in bytes, but it's
# better to leave some margin. For instance specify an amount of RAM
# that's more or less between 60 and 80% of your free RAM.
vm-max-memory 0
# Redis swap files is split into pages. An object can be saved using multiple
# contiguous pages, but pages can't be shared between different objects.
# So if your page is too big, small objects swapped out on disk will waste
# a lot of space. If you page is too small, there is less space in the swap
# file (assuming you configured the same number of total swap file pages).
#
# If you use a lot of small objects, use a page size of 64 or 32 bytes.
# If you use a lot of big objects, use a bigger page size.
# If unsure, use the default :)
vm-page-size 32
# Number of total memory pages in the swap file.
# Given that the page table (a bitmap of free/used pages) is taken in memory,
# every 8 pages on disk will consume 1 byte of RAM.
#
# The total swap size is vm-page-size * vm-pages
#
# With the default of 32-bytes memory pages and 134217728 pages Redis will
# use a 4 GB swap file, that will use 16 MB of RAM for the page table.
#
# It's better to use the smallest acceptable value for your application,
# but the default is large in order to work in most conditions.
vm-pages 134217728
# Max number of VM I/O threads running at the same time.
# This threads are used to read/write data from/to swap file, since they
# also encode and decode objects from disk to memory or the reverse, a bigger
# number of threads can help with big objects even if they can't help with
# I/O itself as the physical device may not be able to couple with many
# reads/writes operations at the same time.
#
# The special value of 0 turn off threaded I/O and enables the blocking
# Virtual Memory implementation.
vm-max-threads 4
############################### ADVANCED CONFIG ###############################
# Hashes are encoded in a special way (much more memory efficient) when they
# have at max a given numer of elements, and the biggest element does not
# exceed a given threshold. You can configure this limits with the following
# configuration directives.
hash-max-zipmap-entries 512
hash-max-zipmap-value 64
# Similarly to hashes, small lists are also encoded in a special way in order
# to save a lot of space. The special representation is only used when
# you are under the following limits:
list-max-ziplist-entries 512
list-max-ziplist-value 64
# Sets have a special encoding in just one case: when a set is composed
# of just strings that happens to be integers in radix 10 in the range
# of 64 bit signed integers.
# The following configuration setting sets the limit in the size of the
# set in order to use this special memory saving encoding.
set-max-intset-entries 512
# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
# order to help rehashing the main Redis hash table (the one mapping top-level
# keys to values). The hash table implementation redis uses (see dict.c)
# performs a lazy rehashing: the more operation you run into an hash table
# that is rhashing, the more rehashing "steps" are performed, so if the
# server is idle the rehashing is never complete and some more memory is used
# by the hash table.
#
# The default is to use this millisecond 10 times every second in order to
# active rehashing the main dictionaries, freeing memory when possible.
#
# If unsure:
# use "activerehashing no" if you have hard latency requirements and it is
# not a good thing in your environment that Redis can reply form time to time
# to queries with 2 milliseconds delay.
#
# use "activerehashing yes" if you don't have such hard requirements but
# want to free memory asap when possible.
activerehashing yes
################################## INCLUDES ###################################
# Include one or more other config files here. This is useful if you
# have a standard template that goes to all redis server but also need
# to customize a few per-server settings. Include files can include
# other files, so use this wisely.
#
# include /path/to/local.conf
# include /path/to/other.conf