From: Srini Bala (sbala@citadon.com)
Date: Sun Mar 09 2003 - 18:01:57 EST
All,
I wanted to know the best design approach in attaching 2xA1000s to 2xE4500s.
Each 4500 has a DB instance running on it and uses the attached A1000 for the
data files storage. Both A1000s are attached to both the A1000s to let the
Vertias Cluster Software to fail the DB instances over to the other machine,
along with the volumes, when there is a fail-over requirement.
Here is the design conflict we are running into. Machine A should use a1000-1
primarily and machine B should use a1000-2 primarily. This is planned to
spread the I/O of both the DB instances on to the separate A1000s.
1. To avoid single point of failure in case of the A1000s (the RAID controller
as well as the back plane are single points of failure, the failure of which
could make the data files inaccessible), we are thinking about mirroring the
LUNs across the two A1000s uisng veritas volume manager. Will it be a good
idea to mirror the LUNs across both the A1000s, as we are concerned about the
I/O of the mirrored LUN affecting the I/O of the other LUN residing on that
A1000 (which is the primary for the DB instance running on that E4500)?
2. If we create Raid manager's own raided mirrors within the same A1000, the
I/O is restricted within that A1000 and doesn't affect the other A1000, but we
know that single points of failure like back plane failure or RAID controller
failure can be catastrophic.
3. Third option which we are thinking about is to have a third mirror on the
second A1000 for an already mirrored LUN on the first A1000. But this is not
very different from the first option.
What are the best practices in the industry for a scaenrio like ours, where a
symmetric failover (both E4500s have DB instances running and they fail-over
criss-cross) is implemented and we want both the DB instances not to compete
for I/O resources?
Are there any other alternatives, like adding a third/fourth A1000, to help
alleviate the I/O contention, as both our DB servers need high I/O capacity.
Any help would be appreciated.
Thanks in advance.
-Srini
_______________________________________________
sunmanagers mailing list
sunmanagers@sunmanagers.org
http://www.sunmanagers.org/mailman/listinfo/sunmanagers
This archive was generated by hypermail 2.1.7 : Wed Apr 09 2008 - 23:25:57 EDT