From: Gavin Davies 
Sent: 28 November 2006 13:46
To: Patrick, GN (Glenn)
Subject: Re: UK Tier 1 and Tier 2 computing requests for 2007 *****

Dear Glenn,

Apologies for the delayed reply.

DØ's request for 2007 is attached.

As usual our request is based around two main things:

a) DØ's computing model is based on distributed computing / grid
      - with UK playing a major role and used to 'pay in kind' our common fund 
        contribution
      - All MC and most data reprocessing is carried out offsite.

b) Our data sets are increasing, and hence our computing needs.

DØ does not distinguish between a Tier-1 and 2 site for any production task. 
Analysis is for now only carried out at Tier-2 sites.  This and our reliance on 
SAM make our storage requests rather modest.

The approx model we've used before is: total = 1/3 Tier-1 + 2/3 Tier-2 (where 
for us Tier-2 is mainly the northern and London Tier-2's)

We are about to start a data reprocessing cycle which will last ~4 months so 
will as a Collaboration need larger resources early on to carry out this along 
with full MC production.  Hence I've forward loaded the increase over 07 in the 
spreadsheet to reflect this;  if the front loading was done simply as more CPU 
in the 1st 6 months, less in the 2nd 6 months that would also be fine.

For completeness I've shown our expected/desired evolution:

		Yr 07	 	Yr 08		Yr 09
CPU: Tier-1	100 kSI2k	150 kSI2k	200 kSI2k
CPU: Tier-2	200 "		300 "		400 "

Disk: Tier-1	5TB		5TB		5TB
Disk: Tier-2	10TB		20TB		~25TB?

(3GHZ = 1.1kSI2k)

With best wishes,
Gavin