Hub/Switch Installation Guide

Chapter 2 HPSS Planning
HPSS Installation Guide September 2002 143
Release 4.5, Revision 2
and protect the SFS metadata, it is important that each site review this list of “rules” and check to
insure that their site’s backup is consistent with these policies.
The main I/O from Encina SFS is in the transaction log, the actual SFS data files, and media log
archiving. When deciding on the size and number of disks for metadata, keep in mind the
following:
1. At a minimum, the transaction log and SFS data files should be on different disks.
2. Ideally, severalphysicaldisks shouldbe availableforSFS datafiles(NS datacan beonone,
BFS data on another, etc.).
3. Themedialog archivingis simplyarunningbackupof thetransactionlog.The transaction
logiswrap-around,butthemedialog archivesarenot. Alargeamountofdataisgenerated
by these archives and must routinely be backed up and removed. A separate disk should
be devoted to the log archives, if possible.
For reliability and availability reasons, the transaction log should be mirrored. The SFS data
volumes should also be mirrored if possible. For performance and reliability reasons, mirroring
should be done using separate physical devices (as opposed to the AIX logical volume being
mirrored to the same physical drive).
2.12.1 Rules for Backing Up SFS Log Volume and MRA Files
Media archiving must alwaysbe enabled while HPSSis running in production mode. If it
isevertemporarily disabled(e.g.,duringa one-timeUniTreemigration),then beforeHPSS
is placed back into production mode, media archiving must be re-enabled and a complete
backup of all SFS data volumes must be made using TRB files.
The SFS log volume must be mirrored on at least two separate physical disks or be stored
on a redundant RAID device.
The file systemused to store MRA filesmust be mirrored onat least twoseparate physical
disks or be stored on a redundant RAID device.
SeparatedisksmustbeusedtostoretheSFSlog volumeversusthefilesystemusedtostore
MRA files.
The latest (i.e., most current) MRA file must never be manipulated, moved, copied, or
deleted since SFS may still be actively writing to it.
MRA files (except the latest) must be copied to tape at least once per day.
MRA files (except the latest) must be copied to at least two different tapes.
2.12.2 Rules for Backing Up SFS Data Volumes and TRB Files
SFS data volumesmustbe mirrored on atleast two separate physicaldisks or be stored on
a redundant RAID device.