Accessing data using HPSS              (Mark Baker)

This page was last updated at 02/04/00 01:30 PM

The HPSS system at RCF is where we store all of our raw data and basic reconstructed data (DSTs).
It consists of a tape robot, some servers (ours is rmds02), and software to access files on tape.
Be careful when accessing HPSS. Besides the obvious possibility of marking our files for deletion,
you could also overload the system and compromise our ability to sink data (or Star's).

All PHOBOS data is stored in one of four "classes of service" (COS): Raw, Recon, Analysis, Archive.
To see the allocations, look here.
To see how much data we've been sinking, look here.
To see how the data is spread across tapes, look here.

We access this data using two accounts:
phobsink: this account is used to sink data to the Raw COS.
phobreco: this account is used for reconstruction on the CRS: input from Raw COS, output to Recon COS.

There are two ways to get data from HPSS:

1. George Heintzelman's clever (but not quite finished) script

This will get all files of type TYPE between MINRUN-MAXRUN inclusive.
If they already exist in the local directory, it won't bother getting them again.
FLAWS: It only takes *s000.root files. Higher sequence files are ignored.
               It seems to skip the first file that it sees, so make MINRUN smaller than you really want.

Note: fetch_pedestal.pl is a misnomer, it can get other types of files as well.

2. The direct, but perhaps more tedious, way