AZURE云上 mkfs.ext4 /dev/sdc 导致宕机问题解决纪实

1、mkfs.ext4后down机

Azure上新建的vm，准备安装oracle数据库，但是挂载的磁盘，初始化后，直接down机了，如下图，失去连接，xshell窗口直接断开退出了。看下面图片

021.png

 

尝试过一下办法：

 

（1）      azure管理界面，重启vm，再来一遍，还是down机。

（2）      删除这台vm，重建一台新的vm，还是一样只要执行mkfs.ext4 /dev/sdc直接down机。

（3）      在别的区建vm，不在东区建在北区建，还是一样。

 

 

2、问题分析

以前附加的磁盘，直接mkfs.ext4 /dev/sdc就可以了，现在为啥不行？去fdisk看磁盘信息：

（1）现在的fdisk –l中的/dev/sdc信息：

Disk /dev/sdc: 1098.4 GB, 1098437885952 bytes

255 heads, 63 sectors/track, 133544 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

 

（2）以前的fdisk –l中的/dev/sdc信息：

Disk /dev/sdd: 1073.7 GB, 1073741824000 bytes

255 heads, 63 sectors/track, 130541 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

 

看到多了“Disk identifier: 0x00000000”信息，正式因为多了这个Disk identifier，才能直接进行mkfs.ext4了。

 

经过google之后，发现Disk identifier需要先分好区才会有，所以新的/dev/sdc磁盘不能直接mkfs.ext4的原因是还没有分好区，要用fdisk分好区之后，再能进行初始化操作。

 

3、fdisk磁盘分区

用fdisk进行磁盘分区：

[root@pldb2 ~]# fdisk /dev/sdc

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Building a new DOS disklabel with disk identifier 0xd788cc0a.

Changes will remain in memory only, until you decide to write them.

After that, of course, the previous content won't be recoverable.

 

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

 

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to

         switch off the mode (command 'c') and change display units to

         sectors (command 'u').

 

Command (m for help): n

Command action

   e   extended

   p   primary partition (1-4)

p

Partition number (1-4): 1

First cylinder (1-133544, default 1):

Using default value 1

Last cylinder, +cylinders or +size{K,M,G} (1-133544, default 133544):

Using default value 133544

 

Command (m for help): m

Command action

   a   toggle a bootable flag

   b   edit bsd disklabel

   c   toggle the dos compatibility flag

   d   delete a partition

   l   list known partition types

   m   print this menu

   n   add a new partition

   o   create a new empty DOS partition table

   p   print the partition table

   q   quit without saving changes

   s   create a new empty Sun disklabel

   t   change a partition's system id

   u   change display/entry units

   v   verify the partition table

   w   write table to disk and exit

   x   extra functionality (experts only)

 

Command (m for help): w

The partition table has been altered!

 

Calling ioctl() to re-read partition table.

Syncing disks.

[root@pldb2 ~]#

 

 

再次查看，会有Disk identifier信息了，也有了新的分区/dev/sdc1，如下：

[root@pldb2 ~]# fdisk -l

 

Disk /dev/sda: 32.2 GB, 32212254720 bytes

255 heads, 63 sectors/track, 3916 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: 0x000c23d3

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1        3789    30432256   83  Linux

/dev/sda2            3789        3917     1024000   82  Linux swap / Solaris

 

Disk /dev/sdb: 240.5 GB, 240518168576 bytes

255 heads, 63 sectors/track, 29241 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: 0x40a7f99c

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1               1       29242   234879936   83  Linux

Disk /dev/sdc: 1098.4 GB, 1098437885952 bytes

255 heads, 63 sectors/track, 133544 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: 0xd788cc0a

 

   Device Boot      Start         End      Blocks   Id  System

/dev/sdc1               1      133544  1072692148+  83  Linux

 

 

 

 

4、mkfs.ext4进行分区初始化

# 使用 mkfs.ext4 命令格式化磁盘成格式化成ext4各式的文件系统。

[root@pldb2 ~]# mkfs.ext4 /dev/sdc1

mke2fs 1.41.12 (17-May-2010)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

67043328 inodes, 268173037 blocks

13408651 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=4294967296

8184 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

         32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,

         4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,

         102400000, 214990848

 

Writing inode tables: done                           

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done

 

This filesystem will be automatically checked every 27 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

[root@pldb2 ~]#

 

 

如下图所示：

22.png

5、挂载磁盘添加启动加载

（1）开始挂载新的分区磁盘到/oracle

[root@pldb2 ~]# mkdir /oracle

[root@pldb2 ~]# mount /dev/sdc1 /oracle

[root@pldb2 ~]#

 

（2）开机启动挂载配置

[root@pldb2 ~]# vim /etc/fstab

You have new mail in /var/spool/mail/root

[root@pldb2 ~]# more /etc/fstab

 

#

# /etc/fstab

# Created by anaconda on Wed Jan 15 04:45:47 2014

#

# Accessible filesystems, by reference, are maintained under '/dev/disk'

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

#

UUID=6d089360-3e14-401d-91d0-378f3fd09332 /                       ext4    defaults        1 1

/dev/sdc1                /oracle                   ext4    defaults        1 2

tmpfs                   /dev/shm                tmpfs   defaults        0 0

devpts                  /dev/pts                devpts  gid=5,mode=620  0 0

sysfs                   /sys                    sysfs   defaults        0 0

proc                    /proc                   proc    defaults        0 0

[root@pldb2 ~]#

 

 

 

OK，磁盘已经准备好了，可以正常安装oracle数据库了。