| 日期 | 作者 | 版本 | 备注 |
|---|---|---|---|
| 2017-06-06 | yangxer | v1.0 | 初版 |
扩容背景：
腾讯云实例上安装的 mysql硬盘空间使用紧张， 购买新的硬盘后计划扩容
# 检查扩容前磁盘使用情况
shell> df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/vda1 ext3 7.9G 4.3G 3.3G 57% /
/dev/vdb xfs 1.5T 1.4T 148G 91% /data
# 检查磁盘情况， 下面显示 /dev/vdd 未有分区
shell> fdisk -l
Disk /dev/vda: 8589 MB, 8589901824 bytes
255 heads, 63 sectors/track, 1044 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: 0x70068116
Device Boot Start End Blocks Id System
/dev/vda1 * 1 1044 8385898+ 83 Linux
Disk /dev/vdb: 1610.6 GB, 1610612736000 bytes
16 heads, 63 sectors/track, 3120761 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/vdc: 2147 MB, 2147483648 bytes
16 heads, 63 sectors/track, 4161 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/vdd: 3221.2 GB, 3221225472000 bytes
16 heads, 63 sectors/track, 6241523 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
# 尝试挂载失败
shell> mount /dev/vdd /data0
mount: you must specify the filesystem type
检查是否安装 parted， 如果没有需要安装
shell> which parted
/sbin/parted
检查是否加载 xfs 模块
shell> lsmod | grep xfs
xfs 1128471 2
exportfs 4236 1 xfs
使用 parted 对大于 2T 的盘进行分区
shell> parted /dev/vdd
GNU Parted 2.1
Using /dev/vdd
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p
Error: /dev/vdd: unrecognised disk label
(parted) mklabel
New disk label type? gpt
# 这个命令将 硬盘容量全部分配到 /dev/vdd1
(parted) mkpart /dev/vdd1 xfs 0% 100%
(parted) p
Model: Virtio Block Device (virtblk)
Disk /dev/vdd: 3221GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number Start End Size File system Name Flags
1 1049kB 3221GB 3221GB /dev/vdd1
(parted) quit
Information: You may need to update /etc/fstab.
格式化分区， 可能会较慢
shell> mkfs.xfs /dev/vdd1
meta-data=/dev/vdd1 isize=256 agcount=4, agsize=196607872 blks
= sectsz=512 attr=2, projid32bit=0
data = bsize=4096 blocks=786431488, imaxpct=5
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal log bsize=4096 blocks=383999, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
查看是否分区成功：
shell> fdisk -l
WARNING: GPT (GUID Partition Table) detected on '/dev/vdd'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/vdd: 3221.2 GB, 3221225472000 bytes
255 heads, 63 sectors/track, 391625 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
Device Boot Start End Blocks Id System
/dev/vdd1 1 267350 2147483647+ ee GPT
shell> ls -l /dev/vdd*
brw-rw---- 1 root disk 252, 48 Jun 6 14:22 /dev/vdd
brw-rw---- 1 root disk 252, 49 Jun 6 14:20 /dev/vdd1
挂载新分区
# 挂载
shell> mount /dev/vdd1 /data0
shell> df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/vda1 ext3 7.9G 4.3G 3.3G 57% /
/dev/vdb xfs 1.5T 1.4T 148G 91% /data
/dev/vdd1 xfs 3.0T 33M 3.0T 1% /data0
# 取消挂载
shell> umount /dev/vdd1
shell> df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/vda1 ext3 7.9G 4.3G 3.3G 57% /
/dev/vdb xfs 1.5T 1.4T 148G 91% /data
写入开机自启动
shell> cat /etc/fstab
/dev/vda1 / ext3 noatime,acl,user_xattr 1 1
LABEL=lswap swap swap defaults 0 0
proc /proc proc defaults 0 0
sysfs /sys sysfs noauto 0 0
debugfs /sys/kernel/debug debugfs noauto 0 0
devpts /dev/pts devpts mode=0620,gid=5 0 0
/dev/vdd1 /data0 xfs defaults 1 2
shell> mount -a
shell> df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/vda1 ext3 7.9G 4.3G 3.3G 57% /
/dev/vdb xfs 1.5T 1.4T 148G 91% /data
/dev/vdd1 xfs 3.0T 33M 3.0T 1% /data0
重启机器验证：
shell> reboot
shell> df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/vda1 ext3 7.9G 4.3G 3.3G 57% /
/dev/vdd1 xfs 3.0T 9.3G 3.0T 1% /data0
/dev/vdb xfs 1.5T 1.4T 148G 91% /data
开启screen, 拷贝数据
shell> screen -S liuys
shell> cp -rp /data/* /data0/
颠倒分区， 启动实例， 卸载旧硬盘， 通知基础运维回收硬盘
注意事项
-
** 扩容时是在从库操作， 将流量引到主库， 并关闭当前从数据库 **
-
** 时间允许可以考虑对两块硬盘进行压测对比， 还可以对 cp前后文件进行 MD5 校验 **
-
** 扩容完成后，直接进行主从切换有性能下降的风险， 因为数据还未load到 buffer_pool 中， 对一个忙碌的数据库应该选择在闲时 **
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