分类：
2009-10-09 23:37:55
How it works
A diskdump is created in a two stage process and works similarly to UNIX-style traditional disk dumps.
The first step is when the kernel itself crashes and the current memory,the CPU state and related information are saved to a reserved partition on a supported disk.
On the next reboot,when the system restarts, the diskdump init scripts will create a vmcore file from the saved information on the reserved partition.
This file will be recreated in the directory /var/crash/with the name127.0.0.1-
Environment:
Red Hat Enterprise Linux 4
Procedure:
Step1:To install diskdumputils package
#up2date dskdumputil
Step2: To configure diskdump, load the diskdump module
#modprobe diskdump
Step3: Check that the module is loaded
#dmesg | tail
header blocks: 3
bitmap blocks: 8
total number of memory blocks: 261999
total blocks written:262010
Step4: The diskdump daemons reserved partition can be specified in the /etc/sysconfig/diskdump
DEVICE=/dev/sde1
Step5: To initialize the partition for use
#service diskdump initialformat
Step6: To add the service to run on startup and then start the service
#chkconfig diskdump on
#service diskdump start
Step7: To save the diskdump image into /var/crash folder,add the following command to /etc/rc.local
#vi /etc/rc.local
savecore –v /dev/
Conclusion：
1.When the diskdump and netdump are set at the same time,diskdump has priority over netdump
2.Diskdump need you to restart the system by yourself
3.diskdump只能dump物理内存里的内容，不能dump交换分区中的内容
4用一块磁盘做diskdump分区只适用于RHEL3，RHEL4上需要使用一个分区来做
5diskdump是直接访问磁盘驱动器，所以使用LV或者RAID方式做的分区不能用来存放dump的内存信息
