System information

18 Sharing and maintaining SLES 10 SP2 Linux under z/VM
򐂰 Checks and mounts /local/ (1B5 disk)
򐂰 Bind mounts /etc/, /srv/ and /root/
This script leaves the root file system in read-only mode after performing a file check on
/local/ directory. The section 1.10.5, “Modified boot.rootfsck file” on page 81 contains a
copy of the modified script.
The boot.findself script will run on the first boot to update the IP address for the new virtual
Linux server. This allows the servers to be cloned with identical IP addresses then updated
on first boot.
1.3.8 Other considerations
The following aspects of the solution were considered at Nationwide Insurance.
Performance
During testing at Nationwide, the changes to read-only root were found to be insignificant to
the overall performance of the Linux systems. The boot process may be slightly faster, since
the I/O request is cached, thus the booting of hundreds of servers will only require one
physical disk read.
Testing multiple server simultaneous starts
Testing at Nationwide entailed starting multiple servers simultaneously (8-12 at a time),
without any identified waits or delays.
Product installations
Installations for the following products were tested at Nationwide:
򐂰 Websphere 6.1
򐂰 Websphere 5.1
򐂰 DB2 UDB Version 8
򐂰 Websphere IHS server
򐂰 Websphere MQ series
Peer Review
The Linux systems administrators at Nationwide reviewed the read-only root environment to
validate that a consistent environment is being retained.
1.4 Summary of virtual machines
Following is a summary of the function of the virtual machines in the system. Refer to
Figure 1-1 on page 4 for a block diagram.
CMSCLONE
This user ID only runs CMS, Linux is never IPLed. It contains the following files:
<userID> PARM-S10 Each Linux guest uses a unique parameter file to get it's host name
and IP
SWAPGEN EXEC Creates VDISK swap space for Linux guests
PROFILE EXEC Profile for all Linux guests. They all link it read-only
CLONERO EXEC Clones a read-only machine from S10GOLD