[gentoo-user] help with transistioning to iSCSI

[Doug O'Neal]

This is not a gentoo-specific question but please bear with me.	 The
computer center I run has a fairly large beowulf cluster, a set of
database servers, and several other specific-purpose servers for a
total of around 175 systems.  Currently there are a half-dozen servers
with local raid arrays used for home directories, which are NFS-exported
and mounted via autofs with LDAP tables.  For a variety of reasons, I am
getting several iSCSI arrays and some of the directories on the file
servers will be migrated to these arrays.  However, a few of the
direct-attach raids will remain as such. The iSCSI arrays will have OCFS
on them and will be mounted on most if not all of the servers. What I am
looking for is a manageable system of handling home directories. I see 3
different scenarios that need to be handled.

Case 1: A home directory is directly attached to hostA.	 If the user logs
into either hostA or hostB, the directory should be automounted.

Case 2: A home directory is on an iSCSI array mounted on both hostA and
hostB.	When the user logs into either of these systems the home directory
should be automounted directly from the iSCSI mount.

Case 3: A home directory is on an iSCSI array mounted on both hostA and
hostB but not on hostC.	 When the user logs into hostC, the home directory
should be automounted from one of the other two hosts.	I could probably
avoid this case with a some effort.
 

I can see a couple of solutions to handle all three cases but they are
all a pain to set up and manage.  I'm not tied to autofs if another
solution is easier and as reliable.  All of the systems in the center are
running gentoo and are kept up to date.	 User authentication is also
handled through ldap so uid/gid consistency is not an issue.

I'd appreciate advice from anyone who has worked though this issue
already.  Thanks.