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This information is important because the user manages the overall system, and the user
runs applications that are needed to make configuration decisions together. The application
user is no longer able to perform simple tasks that they are able to do with diskfull. The use of
statelite, image updates, and postscripts handles the customization. This relationship
continues for the life of the cluster.
Statelite implementation
xCAT is used to implement statelite. The following tables control the data that is read/write or
persistent:
Litefile: Lists the files or directories that are read/write or persistent
Statelite: Lists the NFS server in which the persistent data is stored and mounted from
during a reboot
Litetree: This table is usually left blank.
For more information about how to use these tables and the diskless xCAT procedure, see
this website:
http://sourceforge.net/apps/mediawiki/xcat/index.php?title=XCAT_AIX_Diskless_Nodes
The user must decide which data to include in the litefile table. Any new entries to the litefile
table must be carefully reviewed and tested. This table must be populated before mkdsklsnode
(for AIX) or genimage (for Linux) is run. Example 2-1 shows a litefile table for a Power 775
system.
Example 2-1
litefile table example
# tabdump litefile
#image,file,options,comments,disable
"ALL","/etc/basecust","persistent",,
"ALL","/etc/microcode/","rw",,
"ALL","/gpfslog/","persistent",,
"ALL","/var/adm/ras/errlog","persistent",,
"ALL","/var/adm/ras/gpfslog/","persistent",,
"ALL","/var/mmfs/","persistent",,
"ALL","/var/spool/cron/","persistent",,
Example 2-1includes the following entries:
/etc/basecust
The ODM objectrepos files and directories must not be included in the statelite table. Data
in the ODM must be accessed during boot and before statelite is applied. However, the
user safely mounts the /etc/basecust which stores information about changes that are
made to the ODM. We are using /etc/basecust because the storage nodes boot with
multipath enabled, which is not desirable. Currently, we run a script that removes the
devices, disables multipath, and rediscovers the disk. If /etc/basecust is not added to the
statelite table, we must run /etc/basecust after every reboot, which takes up to one hour
to complete. After /etc/basecust is added to statelite, the second discovery is added to
the ODM and saved on the NFS mounted space.
/etc/microcode
This entry is used so that microcode is placed on the storage nodes to update the disk
enclosure.
Chapter 2. Application integration
101
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