From: Debbie Tropiano (debbie@icus.com)
Date: Wed Apr 16 2003 - 00:54:09 EDT
Hello -
I know that this has been hashed out in the past
(http://www.sunmanagers.org/pipermail/summaries/2002-June/003216.html)
but I have a few further questions about Solaris Volume Manager on
a Solaris 9 system for a two disk system.
The Solaris Volume Manager documentation on docs.sun.com webpage
http://docs.sun.com/db/doc/816-4518/6mannldcj?q=Solaris+Volume+Manager&a=view
under section "Solaris Volume Manager Requirements" that "At least three
replicas should exist ..." and later on webpage
http://docs.sun.com/db/doc/816-4518/6mannldcu?q=Solaris+Volume+Manager&a=view
"A minimum of 3 state database replicas are recommended..." and "For a
system with two to four drives: put two replicas on each drive." but
does not explicitly state that 3 state database replicas are *required*.
Also, the online blueprint Configuring Boot Disks With Solaris Volume
Manager Software (http://www.sun.com/blueprints/1002/817-0407-10.pdf)
when discussing the quorum rule states:
"For this reason, and only in the two-disk configuration, we recommend
that you disable the quorum rule in /etc/system. The system will then
boot unattended, even with one disk."
and later:
"You can choose to force Solstice DiskSuite software to start if half of
the state database replicas are available by setting the tunable
mirrored_root_flag to 1 in /etc/system."
and
"Caution Enable the mirrored_root_flag only if the following prerequisites
are met: 1) The configuration only has two disks. 2) Unattended reboots of a
system with only two disks are a requirement and the risk of booting from a
stale replica, and therefore, stale volume management system state, is
acceptable. This means that in your setup, system availability is more
important than data consistency and integrity. Setting this tunable risks
data corruption or data loss in the event of a transient disk failure, but
allows unattended reboots. See the Solaris Volume Manager documentation on
docs.sun.com for more information about state database replicas (metadbs)."
We have several two disk systems and want to disable the quorum rule,
so we wonder for that situation how many state database replicas are
actually *required* vs recommended. Would having one state database
replica on each disk (for a total of 2 be sufficient)? Also, if we
do have more than one per disk does it really matter if they're both
on a single slice or kept on separate slices? Especially with the
expectation that any failure of the disk will most likely be a total
disk failure.
Thanks in advance,
Debbie
-- + Debbie Tropiano -- debbie@icus.com -- http://www.icus.com/personal.html + | Mommy to Nathan b: 8/17/1995, ^Sara^ b: 10/25/2000 d: 11/7/2000 & | | Leah b: 10/17/2001 a: 9/26/2002 "God shows His opposition to cancer and | | birth defects, not by eliminating them or making them happen only to bad | | people (He can't do that), but by summoning forth friends and neighbors | + to ease the burden and to fill the emptiness." -- Harold S. Kushner + _______________________________________________ sunmanagers mailing list sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagers
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