System information

60 Sharing and maintaining SLES 10 SP2 Linux under z/VM
# updatedb
You have new mail in /var/mail/root
# locate foo | head -1
/opt/gnome/share/icons/hicolor/16x16/stock/navigation/stock_navigator-foonote-body-toggl
e.png
A second test is run on the read-write gold disk. The read-write system running on LNX226 is
shut down and the user ID is logged off. A new read-write Linux system is cloned to LNX226:
==> clonerw lnx226
...
An SSH session is started to the newly cloned LNX226 system. The locate command works
correctly:
# locate foo | head -1
/opt/gnome/share/icons/hicolor/16x16/stock/navigation/stock_navigator-foonote-body-toggl
e.png
This shows that both the /usr/ and /var/ file systems were updated with the locate
command and database, and that the new clone picked up these changes.
Observing the status of the system
The tricky part is keeping track of your system as more and more machines begin sharing the
gold disks. To assist in keeping track of gold disks, the LINKED EXEC was written and is
included in the associated tar file. Here is an example of using it:
==> linked
S10ROGLD LINKS: TEST
S10GOLD LINKS: GOLD 1
LNX227
S10GOLD2 LINKS: [[GOLD 2]]
LNX242
This shows that LNX242 is linked to S10GOLD2. The brackets around GOLD 2 indicate that this
is the most current gold disk, meaning ro2gold2 was the last script to be executed. Both
ro2gold and ro2gold2 write a variable to the file CURGOLD FILE A on the CMSCLONE A disk after
execution to keep track of maintenance progress. In addition, the CLONERO exec also uses the
CURGOLD FILE A in order to make sure the most recently updated gold disk is used when
creating new read-only Linux guests.
1.7.3 Types of software
Different software packages have different styles when implementing it in read-only
environments. The software that can run read-write on a minidisk, or has to be installed in an
entirely read-write environment is easy enough to explain. As is “pure read-only”. The hardest
to explain is the part on “tricking” read-write software to run read-only at least in part by
moving/symlinking the read-write areas to /var/ or /local/, etc. There is no cut and dry
explanation with that since the read-write bits and pieces vary from software to software.
FDRupstream it was a .pid file and some configuration files that needed to be placed
elsewhere, and the installed had to be pre-setup a little to work in the read-only environment.
Software on read-only Linux systems fall into one of four categories:
1. Pure read-only