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RHEL6 学习: Swap 分区扩容

• 数据库

RedHat 企业版 6 默认安装会启用 LVM 管理方式，今天学习了给 swap 分区扩容，这里使用的是给已存在的 swap 逻辑分区扩容的方法，当然也可新建一个 swap 分区逻辑分区。本文采用的是前面的方法，下面是具体步骤。

一 环境信息

1.1 测试环境
平台：笔记本虚拟机
系统：Red Hat Enterprise Linux Server release 6.2

1.2 查看 swap 使用情况

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[root@redhat6 ~]# free -m  
 total used free shared buffers cached  
Mem: 714 665 49 0 38 460  
-/+ buffers/cache: 165 549  
Swap: 1439 0 1439

备注：swap 分区目前为 1439 MB。

1.3 查看硬盘使用情况

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[root@redhat6 ~]# df -hv  
Filesystem Size Used Avail Use% Mounted on  
/dev/mapper/vg_redhat6-lv_root  
 13G 3.5G 8.8G 29% /  
tmpfs 292M 100K 292M 1% /dev/shm  
/dev/sda1 485M 31M 429M 7% /boot

1.4 查看系统 VG 信息

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[root@redhat6 ~]# vgdisplay  
 --- Volume group ---  
 VG Name vg_redhat6 System ID  
 Format lvm2  
 Metadata Areas 1  
 Metadata Sequence No 3  
 VG Access read/write  
 VG Status resizable  
 MAX LV 0  
 Cur LV 2  
 Open LV 2  
 Max PV 0  
 Cur PV 1  
 Act PV 1  
 VG Size 14.51 GiB  
 PE Size 4.00 MiB  
 Total PE 3714  
 Alloc PE / Size 3714 / 14.51 GiB  
 Free PE / Size 0 / 0  
 VG UUID E6cA2U-TL1x-ScCV-UnGU-3Kq4-1u6V-WUb5L4

1.5 查看系统 lv 信息

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[root@redhat6 ~]# lvdisplay  
 --- Logical volume ---  
 LV Name /dev/vg_redhat6/lv_root  
 VG Name vg_redhat6  
 LV UUID QFAl72-FSES-YKAH-Dax1-9FQH-kMmv-8vqju2  
 LV Write Access read/write  
 LV Status available  
 # open 1  
 LV Size 13.10 GiB  
 Current LE 3354  
 Segments 1  
 Allocation inherit  
 Read ahead sectors auto  
 - currently set to 256  
 Block device 253:0  
  
 --- Logical volume ---  
 LV Name /dev/vg_redhat6/lv_swap  
 VG Name vg_redhat6  
 LV UUID H26wg0-bbW2-IfHa-j250-RFFh-O0ze-zTe3VU  
 LV Write Access read/write  
 LV Status available  
 # open 1  
 LV Size 1.41 GiB  
 Current LE 360  
 Segments 1  
 Allocation inherit  
 Read ahead sectors auto  
 - currently set to 256  
 Block device 253:1

备注：根据上面信息，swap 使用的是逻辑卷 vg_redhat6，而且 vg_redhat6 空间都已分配完成，那么要扩 swap 分区，只要扩卷组 vg_redhat6，之后再扩 lv /dev/vg_redhat6/lv_swap 即可。

二 Swap 分区扩容

2.1 笔记本虚拟机加一块 4GB IDE 硬盘

此步略，硬盘加完重启系统后，硬盘信息如下:

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[root@redhat6 ~]# fdisk -l
Disk /dev/sdb: 4294 MB, 4294967296 bytes  
255 heads, 63 sectors/track, 522 cylinders  
Units = cylinders of 16065 * 512 = 8225280 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
I/O size (minimum/optimal): 512 bytes / 512 bytes  
Disk identifier: 0x00000000
Disk /dev/sdb doesn t contain a valid partition table
Disk /dev/sda: 16.1 GB, 16106127360 bytes  
255 heads, 63 sectors/track, 1958 cylinders  
Units = cylinders of 16065 * 512 = 8225280 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
I/O size (minimum/optimal): 512 bytes / 512 bytes  
Disk identifier: 0x000d571a
 Device Boot Start End Blocks Id System  
/dev/sda1 * 1 64 512000 83 Linux  
Partition 1 does not end on cylinder boundary.  
/dev/sda2 64 1959 15215616 8e Linux LVM
Disk /dev/mapper/vg_redhat6-lv_root: 14.1 GB, 14067695616 bytes  
255 heads, 63 sectors/track, 1710 cylinders  
Units = cylinders of 16065 * 512 = 8225280 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
I/O size (minimum/optimal): 512 bytes / 512 bytes  
Disk identifier: 0x00000000
Disk /dev/mapper/vg_redhat6-lv_root doesn t contain a valid partition table
Disk /dev/mapper/vg_redhat6-lv_swap: 1509 MB, 1509949440 bytes  
255 heads, 63 sectors/track, 183 cylinders  
Units = cylinders of 16065 * 512 = 8225280 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
I/O size (minimum/optimal): 512 bytes / 512 bytes  
Disk identifier: 0x00000000
Disk /dev/mapper/vg_redhat6-lv_swap doesn t contain a valid partition table

备注：系统已经认出新加的盘 /dev/sdb， 容量为 4294 MB。

2.2 给VG vg_redhat6 扩容 4 GB

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[root@redhat6 ~]# mkfs.ext4 -t ext4 -c /dev/sdbmke2fs 1.41.12 (17-May-2010)
[root@redhat6 ~]# pvcreate /dev/sdb  
 Writing physical volume data to disk "/dev/sdb"  
 Physical volume "/dev/sdb" successfully created  
  
[root@redhat6 ~]# pvscan  
 PV /dev/sda2 VG vg_redhat6 lvm2 [14.51 GiB / 0 free]  
 PV /dev/sdb lvm2 [4.00 GiB]  
 Total: 2 [18.51 GiB] / in use: 1 [14.51 GiB] / in no VG: 1 [4.00 GiB]  
  
[root@redhat6 ~]# vgextend vg_redhat6 /dev/sdb Volume group "vg_redhat6" successfully extended

2.3 再次查看 vg_redhat6 信息

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[root@redhat6 ~]# vgdisplay  
 --- Volume group ---  
 VG Name vg_redhat6  
 System ID  
 Format lvm2  
 Metadata Areas 2  
 Metadata Sequence No 4  
 VG Access read/write  
 VG Status resizable  
 MAX LV 0  
 Cur LV 2  
 Open LV 2  
 Max PV 0  
 Cur PV 2  
 Act PV 2  
 VG Size 18.50 GiB  
 PE Size 4.00 MiB  
 Total PE 4737  
 Alloc PE / Size 3714 / 14.51 GiB  
 Free PE / Size 1023 / 4.00 GiB  
 VG UUID E6cA2U-TL1x-ScCV-UnGU-3Kq4-1u6V-WUb5L4

备注： VG vg_redhat6 扩容成功。

2.4 停用 swap

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[root@redhat6 ~]# swapoff -v /dev/vg_redhat6/lv_swap  
swapoff on /dev/vg_redhat6/lv_swap

2.5 给 dev/vg_redhat6/lv_swap 扩容 512M

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[root@redhat6 ~]# lvresize -L+512M /dev/vg_redhat6/lv_swap  
 Extending logical volume lv_swap to 1.91 GiB  
 Logical volume lv_swap successfully resized

2.6 格式化 swap 分区

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[root@redhat6 ~]# mkswap /dev/vg_redhat6/lv_swap  
mkswap: /dev/vg_redhat6/lv_swap: warning: dont erase bootbits sectors  
 on whole disk. Use -f to force.  
Setting up swapspace version 1, size = 1998844 KiB  
no label, UUID=47f6e518-6189-4231-9aed-9f7ad01c29ca

2.7 启用 swap

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[root@redhat6 ~]# swapon -v /dev/vg_redhat6/lv_swap  
swapon on /dev/vg_redhat6/lv_swap  
swapon: /dev/mapper/vg_redhat6-lv_swap: found swap signature: version 1, page-size 4, same byte order  
swapon: /dev/mapper/vg_redhat6-lv_swap: pagesize=4096, swapsize=2046820352, devsize=2046820352

2.8 再次查看 swap 验证

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[root@redhat6 ~]# free -m  
 total used free shared buffers cached  
Mem: 582 509 73 0 53 271  
-/+ buffers/cache: 183 399  
Swap: 1951 0 1951

备注： swap 分区成功扩容到 1951 MB。

原创文章，作者：3628473679，如若转载，请注明出处：https://blog.ytso.com/237833.html

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