CentOS显示内存与实际硬件内存大小不一致

购买的服务器写的内存是 2GB,但是从宝塔看只用 1800 多 MB...

先用free看一下:

              total        used        free      shared  buff/cache   available
Mem:        1882000      422140      682784         776      777076     1283632
Swap:       1049596       40448     1009148

查看内核预留内存:dmesg | grep -i memory

[    0.000000] Base memory trampoline at [ffff9eb200099000] 99000 size 24576
[    0.000000] Reserving 161MB of memory at 688MB for crashkernel (System RAM: 2047MB)
[    0.000000] Early memory node ranges
[    0.000000] PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff]
[    0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000effff]
[    0.000000] PM: Registered nosave memory: [mem 0x000f0000-0x000fffff]
[    0.000000] Memory: 1858740k/2097008k available (7788k kernel code, 392k absent, 237876k reserved, 5954k data, 1984k init)
[    0.000000] please try 'cgroup_disable=memory' option if you don't want memory cgroups
[    0.331747] Initializing cgroup subsys memory
[    0.475802] x86/mm: Memory block size: 128MB
[    1.231809] Freeing initrd memory: 20320k freed
[    1.349328] Non-volatile memory driver v1.3
[    1.352113] crash memory driver: version 1.1
[    1.498955] Freeing unused kernel memory: 1984k freed
[    1.502904] Freeing unused kernel memory: 392k freed
[    1.505199] Freeing unused kernel memory: 536k freed
[    2.262990] [TTM] Zone  kernel: Available graphics memory: 941000 kiB

crashkernel保留了161MB的内存，属于kdump服务.

停止并关闭kdump

systemctl stop kdump
systemctl disable kdump

修改grub文件(宝塔直接在线改就好)

vi /etc/default/grub

将crashkernel=auto改为crashkernel=0
如:

GRUB_TIMEOUT=5#请无视本行
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"#请无视本行
GRUB_DEFAULT=saved#请无视本行
GRUB_DISABLE_SUBMENU=true#请无视本行
GRUB_TERMINAL_OUTPUT="console"#请无视本行
GRUB_CMDLINE_LINUX="crashkernel=0 resume=UUID=XXXX-XXXX-XXXX-XXXX-XXXX" #改动此行
GRUB_DISABLE_RECOVERY="true"#请无视本行
GRUB_ENABLE_BLSCFG=true#请无视本行

更新grub配置文件、重启系统

grub2-mkconfig -o /boot/grub2/grub.cfg
reboot

你就会发现内存变多了..

~谢谢打赏~

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