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,several physical disks should be available for SFS data files (NS data can be on one,
BFS data on another, etc.).
3. Themedia log archiving is simply a running backup of the transaction log. The transaction
logis wrap-around, but the media log archives are not. A large amount of data is generated
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 always be enabled while HPSS is running in production mode. Ifit
isever temporarily disabled (e.g., during a one-time UniTree migration), then before HPSS
isplaced 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 system used to store MRA files must be mirrored on at least two separate physical
disks or be stored on a redundant RAID device.
• Separate disks must be used to store the SFS log volume versus the file system used to store
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 volumes must be mirrored on at least two separate physical disks or be stored on
a redundant RAID device.