Jeff
I worked with Kem and updated the numbers in the storage estimate
spreadsheet. To be consistent with SRD, we: changed
- number of fields: 2,500 --> 1,875
- number of sq deg: 25,000 --> 15,000
This brought down the total size by ~17%, e.g. 600 --> 500 TB
for the first year.
The updated spreadsheet is in Docushare, Collection-413
I expect more changes coming (related to Tim's comments),
so this is likely not the final version.
Jacek
Jeffrey P Kantor wrote:
Hi Kem,
Per the definitions in the SRD, we should be estimating to the design spec.
We consider the stretch goal if it does not materially increase cost,
schedule, or risk. In this case, the stretch goal would appear to
significantly increase cost.
Jeff
From: "Kem Cook" <[EMAIL PROTECTED]>
Reply-To: LSST Data Management <[email protected]>
Date: Wed, 12 Jul 2006 13:25:45 -0700 (PDT)
To: "LSST Data Management" <[email protected]>
Subject: Re: [LSST-data] Notes from Database telecon Wed Jul 12
Keywords: DataAccWG
database storage estimates
- latest version uses input from Zeljko, database size
increased by ~50%
- now it is 600 TB data after the first year
- Tim: number of sources seems too large, will check the
spreadsheet in more details and start email discussion
The current numbers use the number of visits per field-filter needed for
the weak lensing for all fields and this is clearly not correct for the
Galactic plane/bulge fields. It is those fields in the red filters which
are driving the number of objects. So, the catalog has the correct
numbers, but the temporal database is overestimated. I thought the
science council was going to provide some guidance on observing
cadences/frequencies for Galactic fields, but haven't heard anything.
Until we have an idea what the cadences/frequencies are we might as well
stick with the conservative (overly large) estimate we have.
I must admit to a bit of sloppiness in mixing design and stretch goals.
We have been assuming 1000 visits for the weak lensing fields (design
goal) and 20,000 square degrees (stretch goal). So, a question for Jeff
(&Tim) should we be sizing for the design numbers or the stretch numbers?
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