Len Boyle writes:

>    Does  anyone have  an estimate  for the  average space  used for  the
>    catalog space for  each object. I believe someone  reported 600 bytes
>    per file.  But this seems  high for an  average when the  objects are
>    compressed.
>
>    For 1 million files x 600 bytes x 2 for duplexing x 10 for
>    10 generations or cycles this is 1.2 x 10 to the 10th power.


I think I was the one who reported the number for WDSF. It comes from the
WDSF Administrator's Guide, p 15:

  Database space(in 3380 equivalent cylinders) = Total files/1050(files/cyl)

At 600k per cylinder, this comes to 585 bytes/file.

As Len points out, the ADSM documentation doesn't provide similar planning
rules of thumb (This is a significant omission, I believe). We aren't running
ADSM in production yet and have just run some preliminary server tests.
These early results, for a two clients (one MS Windows, one AIX) indicate
the following:

  # of files = 38,000 (from q occ)
  # of used database pages = 7600 = (at 4k bytes/page)  30M bytes

  bytes/file = 30M/38000 = 830

This estimate may be a bit high as the q occ command (see one of my previous
appends) only reports the # of files, not the total # of objects. Even giving
them the benefit of the doubt, the estimate of 600 bytes/file is still
the right order of magnitude.

Hence, the computation appears about right. For a million files, 10 generations,
2 copies, you need about 10 gigabytes for the database.

Regards, MK