CAS 启动无法进入系统解决方法

CAS主机发生重启，提示挂载目录失败，

An error occurred while mounting /vms/host.

Press S to skip mounting or M for manual recovery

首先，我们可以按S跳过挂载该目录，使CAS系统正常启动起来。待CAS启动起来后，再分析具体原因。

如上提示，现场环境为服务器有2个raid1，2个300G硬盘用于装了CAS系统，2个500G硬盘挂载在了/vms/host目录下，供虚拟机使用。等待CAS启动完成后，再次进入CAS系统，发现前台host目录不是500G的空间了，而是和isospool、defaultpool空间一致，并且存放在hosts目录下的虚拟机文件都没有了，如图：

Cas后台查看磁盘挂载如下：

root@cvm:~# df -h

Filesystem      Size  Used Avail Use% Mounted on

/dev/sda1        28G  4.0G   22G  16% /

udev             16G   12K   16G   1% /dev

tmpfs           6.3G  372K  6.3G   1% /run

none            5.0M     0  5.0M   0% /run/lock

none             16G   12K   16G   1% /run/shm

cgroup           16G     0   16G   0% /sys/fs/cgroup

/dev/sda5        19G  1.5G   16G   9% /var/log

/dev/sda7       221G   33G  177G   16% /vms

/dev/sda6        221G   33G  177G  16% /vms/host

Sda6挂载到了/vms/host目录下了，而sda6为swap分区：

root@cvm:~# fdisk -l

Disk /dev/sda: 300.0 GB, 299966445568 bytes

255 heads, 63 sectors/track, 36468 cylinders, total 585871964 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 262144 bytes / 262144 bytes

Disk identifier: 0x00051c5a

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *         512    58593791    29296640   83  Linux

/dev/sda2        58594302   585871359   263638529    5  Extended

Partition 2 does not start on physical sector boundary.

/dev/sda5        58594304    97656319    19531008   83  Linux

/dev/sda6        97656832   115263487     8803328   82  Linux swap / Solaris

/dev/sda7       115264000   585871359   235303680   83  Linux

最后查看fstab文件：

root@cvm:~# more /etc/fstab

# /etc/fstab: static file system information.

#

# Use 'blkid' to print the universally unique identifier for a

# device; this may be used with UUID= as a more robust way to name devices

# that works even if disks are added and removed. See fstab(5).

#

#              

proc            /proc           proc    nodev,noexec,nosuid 0       0

# / was on /dev/sda1 during installation

UUID=1a66bc40-75c6-48b6-9d95-158b0598a722 /               ext4    errors=remount-ro 0       1

# /var/log was on /dev/sda5 during installation

UUID=272cc474-8961-4874-b14c-e7a629dad0a7 /var/log        ext4    defaults        0       2

# /vms was on /dev/sda7 during installation

UUID=17cbed60-a039-4b91-a0c8-76633a94a69c /vms            ext4    defaults        0       2

# swap was on /dev/sda6 during installation

UUID= 50909a9e-3ba6-440e-b815-29774d00f2ea /vms/host       ext4    defaults         0       0

查看sda6的uuid：

root@cvm:~# blkid /dev/sda6

/dev/sda6: UUID="50909a9e-3ba6-440e-b815-29774d00f2ea" TYPE="swap"

通过上面可以判断为：挂载sdb分区修改fstab的时候直接修改了交换分区的信息，但是cas启动的时候是需要交换分区的，系统进行了重置。导致了该问题。

1、在CAS前台界面将该主机的host存储池暂停；

2、查询记录sdb的uuid信息：

root@cvm:~# blkid /dev/sdb

/dev/sdb: UUID="75ab245f-eb96-44d3-96dd-abc4907f3155" TYPE="ext4"

3、修改fstab文件，将swap分区修改正确，并且增加新的挂载点：

root@cvm:~# vim /etc/fstab

# /etc/fstab: static file system information.

#

# Use 'blkid' to print the universally unique identifier for a

# device; this may be used with UUID= as a more robust way to name devices

# that works even if disks are added and removed. See fstab(5).

#

#              

proc            /proc           proc    nodev,noexec,nosuid 0       0

# / was on /dev/sda1 during installation

UUID=1a66bc40-75c6-48b6-9d95-158b0598a722 /               ext4    errors=remount-ro 0       1

# /var/log was on /dev/sda5 during installation

UUID=272cc474-8961-4874-b14c-e7a629dad0a7 /var/log        ext4    defaults        0       2

# /vms was on /dev/sda7 during installation

UUID=17cbed60-a039-4b91-a0c8-76633a94a69c /vms            ext4    defaults        0       2

# swap was on /dev/sda6 during installation

UUID=50909a9e-3ba6-440e-b815-29774d00f2ea none            swap    sw            0       0

UUID=75ab245f-eb96-44d3-96dd-abc4907f3155 /vms/host         ext4    defaults        0       0

4、将sda6 umount：umount /vms/host；然后重启mount：mount -a

5、在CAS前台界面将该主机的host存储池启用，检查各个虚拟机运行状态是否正常。

修改CAS后台文件严格按照指导书操作，严禁私自修改系统各个文件。