在系统安装的时候，由于经验不足或者是规划的问题，分区的时候往往会有一定的考虑不全面，当使用一定的时间就会发现某个分区空间严重的不足。这时我们通常会想到分区扩容，但是为了保证业务的连续性和高可用，我们需要快捷的扩容和平移应用目录，下面我们来看一个实际的扩容案例。
背景环境：两台SUSE LINUX10企业版服务器+WAS集群(一台主节点+一台从节点)+NFS共享文件系统(basefs)
一、查看现有的分区系统
主节点：10.4.12.112
ty1:~ # df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda2 38G 12G 27G 99% /
udev 7.9G 88K 7.9G 1% /dev
从节点：10.4.12.113
ty2:~ # df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda2 38G 7.6G 31G 20% /
udev 7.9G 92K 7.9G 1% /dev
10.4.12.112:/basefs 38G 12G 27G 99% /basefs
现有的情况是两个主机使用一个NFS的共享文件系统。10.4.12.112是NFS的主服务器，设置了根下basefs的共享目录，而10.4.12.113是NFS的一个客户端，挂载的是112服务器上的basefs共享目录。这个BASEFS的共享目录与WEBSPHERE APPLICATION SERVER(简称WAS)集群上的应用密切相关。
二、扩容思路：挂载一个107G大小的scsi磁盘，把它单独划成一个分区，然后将basefs目录里的所有内容迁移到新的分区上，新分区挂载目录的名字仍为basefs。可以将原basefs目录改名或删除。
三、扩容实施过程：
1、建立分区
ty1:~ # fdisk -l
Disk /dev/sda: 107.3 GB, 107374182400 bytes （挂载的SCSI磁盘）
16 heads, 255 sectors/track, 51400 cylinders
Units = cylinders of 4080 * 512 = 2088960 bytes
Disk /dev/sda doesn't contain a valid partition table
Disk /dev/hda: 42.9 GB, 42949672960 bytes （原磁盘）
255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/hda1 1 262 2104483+ 82 Linux swap / Solaris
/dev/hda2 * 263 5221 39833167+ 83 Linux
You have new mail in /var/mail/root
在SCSI磁盘上建立一个新的分区
ty1:~ # fdisk /dev/sda
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
The number of cylinders for this disk is set to 51400.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): p
Disk /dev/sda: 107.3 GB, 107374182400 bytes
16 heads, 255 sectors/track, 51400 cylinders
Units = cylinders of 4080 * 512 = 2088960 bytes
Device Boot Start End Blocks Id System
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-51400, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-51400, default 51400):
Using default value 51400
Command (m for help): p
Disk /dev/sda: 107.3 GB, 107374182400 bytes
16 heads, 255 sectors/track, 51400 cylinders
Units = cylinders of 4080 * 512 = 2088960 bytes
Device Boot Start End Blocks Id System
/dev/sda1 1 51400 104855872+ 83 Linux
Partition 1 does not end on cylinder boundary.
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
格式化新建的分区
ty1:~ # mkfs.ext3 /dev/sda1
mke2fs 1.38 (30-Jun-2005)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
13107200 inodes, 26213968 blocks
1310698 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
800 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information:
done
This filesystem will be automatically checked every 20 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
You have new mail in /var/mail/root
ty1:~ # pwd
/
ty1:~ # mkdir aaa
ty1:~ # mount /dev/sda1 /aaa
ty1:~ # df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda2 38G 12G 27G 99% /
udev 7.9G 92K 7.9G 1% /dev
/dev/sda1 99G 188M 94G 1% /aaa
2、应用迁移
停止112和113的NFS应用
#/etc/init.d/nfsserver stop
#/etc/init.d/portmap stop
停止112和113的IHS、WAS
#cd /usr/IBM/HTTPServer/bin
./adminctl stop
./apachectl stop
#cd /usr/IBM/AppServer/profiles/AppSrv01/bin
./stopServer.sh server1
./stopNode.sh
#cd /usr/IBM/AppServer/profiles/Dmgr01/bin
./stopManager.sh
113解挂NFS
#umount /basefs
112主节点的WAS服务器：
将原/BASEFS下的四个目录分别打一个TAR包，放到/AAA目录下解压还原（或通过cp -ra smap /aaa也可将目录平移并保留原有的权限和属性）
将原/BASEFS改名为其他，把/AAA目录改为/BASEFS
112启动NFS
#/etc/init.d/portmap start
#/etc/init.d/nfsserver start
113重挂
#mount /10.4.12.112:/basefs /basefs
启动112和113的WAS、HIS应用
启动IHS WAS
#cd /usr/IBM/HTTPServer/bin
./adminctl start
./apachectl start
#cd /usr/IBM/AppServer/profiles/AppSrv01/bin
./startServer.sh server1
./startNode.sh
#cd /usr/IBM/AppServer/profiles/Dmgr01/bin
./startManager.sh
三、验证测试
1、df –h验证分区扩容是否正常
ty1:~ # df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda2 38G 12G 27G 29% /
udev 7.9G 92K 7.9G 1% /dev
/dev/sda1 99G 25G 74G 25% /basefs
ty2:~ # df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda2 38G 7.6G 31G 20% /
udev 7.9G 92K 7.9G 1% /dev
10.4.12.112:/basefs 99G 25G 74G 25% /basefs
2、应用开发人员测试程序是否正常
3、不正常则停止应用改回原BASEFS目录进行回退
最后经验证，一切正常，扩容成功。