Linux設置虛擬內存教學和實戰

時間  2019-11-09
標籤 linux 設置 虛擬 內存 教學 實戰 欄目 Linux 简体版
原文   原文鏈接

介紹

在咱們本身的購買的服務器環境中，通常是買的1g的內存，可是當服務器裏面的東西裝的比較多的時候就會致使內存不夠用了，本文將模擬一個真實的內存不夠用的狀況下，如何經過修改虛擬內存來讓系統正常運行，咱們這裏的環境是搭建一個ElasticSearch搜索的環境，可是咱們的服務器內存只有1g，下面將演示如何在將1g的虛擬內存修改成4G。java

搭建ElasticSearch環境

如今咱們的服務器環境是空的，什麼都沒有，咱們這裏先將ElasticSearch上傳到服務器，而後將jdk和ElasticSearch安裝好。node

安裝jdk

安裝教程後面更新（該文章主要介紹設置虛擬內存，安裝這些東西主要是模擬一個內存不夠的狀態）sql

安裝ElasticSearch

安裝連接後面更新（該文章主要介紹設置虛擬內存，安裝這些東西主要是模擬一個內存不夠的狀態）express

啓動ElasticSearch

  1. 啓動ElasticSearch，會發現啓動的時候報錯了，緣由是咱們的服務器如今的內存並不能知足ElasticSearch須要的內存。
[esyonghu@localhost elasticsearch-6.4.0]$ ./bin/elasticsearch 
[1] 3228
[esyonghu@localhost elasticsearch-6.4.0]$ Java HotSpot(TM) 64-Bit Server VM warning: INFO: os::commit_memory(0x000000008a660000, 1973026816, 0) failed; error='Cannot allocate memory' (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 1973026816 bytes for committing reserved memory.
# An error report file with more information is saved as:
# logs/hs_err_pid3228.log
[esyonghu@localhost elasticsearch-6.4.0]$ 
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  1. 查看咱們的服務器的內存，使用命令 free,能夠看到咱們服務器的內存是1g, 這個時候就須要咱們修改虛擬內存來解決該問題了。
[esyonghu@localhost elasticsearch-6.4.0]$ free -m
             total       used       free     shared    buffers     cached
Mem:           980        582        397          2         23        245
-/+ buffers/cache:        313        667
Swap:            0          0          0
[esyonghu@localhost elasticsearch-6.4.0]$ 
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建立swap文件

  1. 進入/usr目錄
[root@localhost usr]$ pwd
/usr
[root@localhost usr]$ 
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  1. 建立swap文件夾,並進入該文件夾
[root@localhost usr]# mkdir swap
[root@localhost usr]# cd swap/
[root@localhost swap]# pwd
/usr/swap
[root@localhost swap]# 
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  1. 建立swapfile文件,使用命令dd if=/dev/zero of=/usr/swap/swapfile bs=1M count=4096
[root@localhost swap]# dd if=/dev/zero of=/usr/swap/swapfile bs=1M count=4096
記錄了4096+0 的讀入
記錄了4096+0 的寫出
4294967296字節(4.3 GB)已複製，15.7479 秒，273 MB/秒
[root@localhost swap]#
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查看swap文件

  1. 使用命令du -sh /usr/swap/swapfile,能夠看到咱們建立的這個swap文件爲4g
[root@localhost swap]# du -sh /usr/swap/swapfile
4.1G	/usr/swap/swapfile
[root@localhost swap]# 
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將目標設置爲swap分區文件

  1. 使用命令mkswap /usr/swap/swapfile將swapfile文件設置爲swap分區文件
[root@localhost swap]# mkswap /usr/swap/swapfile
mkswap: /usr/swap/swapfile: warning: don't erase bootbits sectors on whole disk. Use -f to force. Setting up swapspace version 1, size = 4194300 KiB no label, UUID=5bd241ff-5375-449d-9975-5fdd429df784 [root@localhost swap]# 複製代碼

激活swap區，並當即啓用交換區文件

  1. 使用命令swapon /usr/swap/swapfile
[root@localhost swap]# swapon /usr/swap/swapfile
[root@localhost swap]#
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  1. 使用命令free -m 來查看如今的內存,能夠看到裏面的Swap分區變成了4095M，也就是4G內存。
[root@localhost swap]# free -m
             total       used       free     shared    buffers     cached
Mem:           980        910         70          3          8        575
-/+ buffers/cache:        326        654
Swap:         4095          0       4095
[root@localhost swap]#
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設置開機自動啓用虛擬內存，在etc/fstab文件中加入以下命令

  1. 使用vim編輯器打開/etc/fstab文件bootstrap

  2. 在文件中加入以下內容vim

/usr/swap/swapfile swap swap defaults 0 0
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使用reboot命令重啓服務器

  1. 輸入reboot 命令來重啓
[root@localhost swap]# reboot

	Broadcast message from liaocheng@localhost.localdomain
		(/dev/pts/1) at 3:56 ...

	The system is going down for reboot NOW!
	[root@localhost swap]# Connection to 192.168.136.142 closed by remote host.
	Connection to 192.168.136.142 closed.
	[進程已完成]
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  1. 重啓完成事後使用free -m 命令來查看如今的內存是否掛在上了。
[root@localhost swap]# free -m
             total       used       free     shared    buffers     cached
Mem:           980        910         70          3          8        575
-/+ buffers/cache:        326        654
Swap:         4095          0       4095
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再次啓動ElasticSearch看看是否還會報內存不足的錯誤

  1. 仍是切換到esyonghu去啓動（這裏爲何要使用es用戶啓動就先不介紹了，這是elasticsearch裏面的知識，這裏只是用elasticsearch來模擬內存不足的狀況）,能夠看到已經不會有內存不足的問題了。
[esyonghu@localhost elasticsearch-6.4.0]$ ./bin/elasticsearch &
[1] 2898
[esyonghu@localhost elasticsearch-6.4.0]$ [2019-03-06T04:00:24,841][INFO ][o.e.n.Node               ] [] initializing ...
[2019-03-06T04:00:24,928][INFO ][o.e.e.NodeEnvironment    ] [dMy5nR5] using [1] data paths, mounts [[/ (rootfs)]], net usable_space [7.6gb], net total_space [17.3gb], types [rootfs]
[2019-03-06T04:00:24,928][INFO ][o.e.e.NodeEnvironment    ] [dMy5nR5] heap size [1.9gb], compressed ordinary object pointers [true]
[2019-03-06T04:00:25,018][INFO ][o.e.n.Node               ] [dMy5nR5] node name derived from node ID [dMy5nR5fThaBb-Q2T0txdA]; set [node.name] to override
[2019-03-06T04:00:25,018][INFO ][o.e.n.Node               ] [dMy5nR5] version[6.4.0], pid[2898], build[default/tar/595516e/2018-08-17T23:18:47.308994Z], OS[Linux/2.6.32-696.el6.x86_64/amd64], JVM[Oracle Corporation/Java HotSpot(TM) 64-Bit Server VM/1.8.0_181/25.181-b13]
[2019-03-06T04:00:25,018][INFO ][o.e.n.Node               ] [dMy5nR5] JVM arguments [-Xms2g, -Xmx2g, -XX:+UseConcMarkSweepGC, -XX:CMSInitiatingOccupancyFraction=75, -XX:+UseCMSInitiatingOccupancyOnly, -XX:+AlwaysPreTouch, -Xss1m, -Djava.awt.headless=true, -Dfile.encoding=UTF-8, -Djna.nosys=true, -XX:-OmitStackTraceInFastThrow, -Dio.netty.noUnsafe=true, -Dio.netty.noKeySetOptimization=true, -Dio.netty.recycler.maxCapacityPerThread=0, -Dlog4j.shutdownHookEnabled=false, -Dlog4j2.disable.jmx=true, -Djava.io.tmpdir=/tmp/elasticsearch.24Q3S9AE, -XX:+HeapDumpOnOutOfMemoryError, -XX:HeapDumpPath=data, -XX:ErrorFile=logs/hs_err_pid%p.log, -XX:+PrintGCDetails, -XX:+PrintGCDateStamps, -XX:+PrintTenuringDistribution, -XX:+PrintGCApplicationStoppedTime, -Xloggc:logs/gc.log, -XX:+UseGCLogFileRotation, -XX:NumberOfGCLogFiles=32, -XX:GCLogFileSize=64m, -Des.path.home=/home/esyonghu/elasticsearch-6.4.0, -Des.path.conf=/home/esyonghu/elasticsearch-6.4.0/config, -Des.distribution.flavor=default, -Des.distribution.type=tar]
[2019-03-06T04:00:28,022][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [aggs-matrix-stats]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [analysis-common]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [ingest-common]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [lang-expression]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [lang-mustache]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [lang-painless]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [mapper-extras]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [parent-join]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [percolator]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [rank-eval]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [reindex]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [repository-url]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [transport-netty4]
[2019-03-06T04:00:28,023][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [tribe]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-core]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-deprecation]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-graph]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-logstash]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-ml]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-monitoring]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-rollup]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-security]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-sql]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-upgrade]
[2019-03-06T04:00:28,024][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded module [x-pack-watcher]
[2019-03-06T04:00:28,025][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded plugin [analysis-ik]
[2019-03-06T04:00:28,025][INFO ][o.e.p.PluginsService     ] [dMy5nR5] loaded plugin [analysis-pinyin]
[2019-03-06T04:00:31,315][INFO ][o.e.x.s.a.s.FileRolesStore] [dMy5nR5] parsed [0] roles from file [/home/esyonghu/elasticsearch-6.4.0/config/roles.yml]
[2019-03-06T04:00:32,017][INFO ][o.e.x.m.j.p.l.CppLogMessageHandler] [controller/2947] [Main.cc@109] controller (64 bit): Version 6.4.0 (Build cf8246175efff5) Copyright (c) 2018 Elasticsearch BV
[2019-03-06T04:00:32,495][DEBUG][o.e.a.ActionModule       ] Using REST wrapper from plugin org.elasticsearch.xpack.security.Security
[2019-03-06T04:00:32,768][INFO ][o.e.d.DiscoveryModule    ] [dMy5nR5] using discovery type [zen]
[2019-03-06T04:00:33,628][INFO ][o.e.n.Node               ] [dMy5nR5] initialized
[2019-03-06T04:00:33,628][INFO ][o.e.n.Node               ] [dMy5nR5] starting ...
[2019-03-06T04:00:33,860][INFO ][o.e.t.TransportService   ] [dMy5nR5] publish_address {192.168.136.142:9300}, bound_addresses {[::]:9300}
[2019-03-06T04:00:33,884][INFO ][o.e.b.BootstrapChecks    ] [dMy5nR5] bound or publishing to a non-loopback address, enforcing bootstrap checks
[2019-03-06T04:00:36,995][INFO ][o.e.c.s.MasterService    ] [dMy5nR5] zen-disco-elected-as-master ([0] nodes joined)[, ], reason: new_master {dMy5nR5}{dMy5nR5fThaBb-Q2T0txdA}{ldgTZ1XZSfOpda9uP4treA}{192.168.136.142}{192.168.136.142:9300}{ml.machine_memory=1028210688, xpack.installed=true, ml.max_open_jobs=20, ml.enabled=true}
[2019-03-06T04:00:37,003][INFO ][o.e.c.s.ClusterApplierService] [dMy5nR5] new_master {dMy5nR5}{dMy5nR5fThaBb-Q2T0txdA}{ldgTZ1XZSfOpda9uP4treA}{192.168.136.142}{192.168.136.142:9300}{ml.machine_memory=1028210688, xpack.installed=true, ml.max_open_jobs=20, ml.enabled=true}, reason: apply cluster state (from master [master {dMy5nR5}{dMy5nR5fThaBb-Q2T0txdA}{ldgTZ1XZSfOpda9uP4treA}{192.168.136.142}{192.168.136.142:9300}{ml.machine_memory=1028210688, xpack.installed=true, ml.max_open_jobs=20, ml.enabled=true} committed version [1] source [zen-disco-elected-as-master ([0] nodes joined)[, ]]])
[2019-03-06T04:00:37,058][INFO ][o.e.x.s.t.n.SecurityNetty4HttpServerTransport] [dMy5nR5] publish_address {192.168.136.142:9200}, bound_addresses {[::]:9200}
[2019-03-06T04:00:37,058][INFO ][o.e.n.Node               ] [dMy5nR5] started
[2019-03-06T04:00:37,177][INFO ][o.w.a.d.Monitor          ] try load config from /home/esyonghu/elasticsearch-6.4.0/config/analysis-ik/IKAnalyzer.cfg.xml
[2019-03-06T04:00:37,179][INFO ][o.w.a.d.Monitor          ] try load config from /home/esyonghu/elasticsearch-6.4.0/plugins/ik/config/IKAnalyzer.cfg.xml
[2019-03-06T04:00:37,888][INFO ][o.e.m.j.JvmGcMonitorService] [dMy5nR5] [gc][4] overhead, spent [486ms] collecting in the last [1.2s]
[2019-03-06T04:00:38,435][WARN ][o.e.x.s.a.s.m.NativeRoleMappingStore] [dMy5nR5] Failed to clear cache for realms [[]]
[2019-03-06T04:00:38,469][INFO ][o.e.l.LicenseService     ] [dMy5nR5] license [c91cae39-79d7-4a0e-b40b-b1918a45f80c] mode [trial] - valid
[2019-03-06T04:00:38,477][INFO ][o.e.g.GatewayService     ] [dMy5nR5] recovered [5] indices into cluster_state
[2019-03-06T04:00:38,902][WARN ][o.e.x.s.a.s.m.NativeRoleMappingStore] [dMy5nR5] Failed to clear cache for realms [[]]
[2019-03-06T04:00:39,106][INFO ][o.e.c.r.a.AllocationService] [dMy5nR5] Cluster health status changed from [RED] to [YELLOW] (reason: [shards started [[mynote2][2]] ...]).
複製代碼
  1. 如今使用free -m來查看內存使用狀況, 能夠看到swap已經被使用了1.7G
[esyonghu@localhost elasticsearch-6.4.0]$ free -m
             total       used       free     shared    buffers     cached
Mem:           980        916         64          0          3         33
-/+ buffers/cache:        880        100
Swap:         4095       1735       2360
[esyonghu@localhost elasticsearch-6.4.0]$
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