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WLCG Data Steering Group
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Europe/Zurich
28/R-015 (CERN)
Description
WLCG Data Steering Group
- Review of Group
- Mandate
- Representation and Structure
- Connection to other groups
- HSF "Data Access and Management" WG
- Round table on priorities
- What strategic issues should the community be addressing, and how?
- Use of forthcoming preGDB slot
- Format for WLCG Workshop (mid-June)
- Next steps
Reference
https://espace.cern.ch/WLCG-document-repository/Boards/MB/Minutes/MB-Minutes-160920-v1.pdf
http://indico.cern.ch/event/467577/contributions/1976036/attachments/1339953/2017450/DataMBSummary.pdf
Thursday 2 Feb 2017
Present
Alastair Dewhurst
Andrew Hanushevsky
Brian Bockelman
Frank Wuerthwein
Pepe Flix
Philippe Charpentier
Michel Jouvin
Paul Millar
Mario Lasnig
Ian Bird
Dirk Duellmann
Martin Barisits
Latchezar Betev
Giuseppe Lo Presti
Julia Andreeva
Oliver Keeble
Review of Group
Mandate
Representation and Structure
Connection to other groups
HSF "Data Access and Management" WG
Round table on priorities
What strategic issues should the community be addressing, and how?
Use of forthcoming preGDB slot
Format for WLCG Workshop (mid-June)
Next steps
##
-- Overview
IB - stress that commonalities are essential
group should focus on strategy, should also contribute to HSF CWP
ultimately will be part of the process for producing the next computing TDRs
FW - most useful would be exchange forum - tell each other what we're doing
exchange for prototypes and ideas
AH -overlap of 25% to 100% with HSF WG, depending on how this group views its mandate.
HSF wg was 25 people or so (big)
Oriented to hi-lumi
Trying to get a single vision
The data access WG doc has been attached to the agenda
https://docs.google.com/document/d/1wEsX2BegSBEZe3EXwdNR9VWNPrNEOVVTLhu-NtH-77E/edit
Will be another meeting in May (??) for HSF
LB - Alice and LHCb have shorter timescales
This group must also be more pragmatic to be relevant for them
No objections to the mandate (see OK's presentation) were raised.
-- Input
- Alice (LB)
Themes of interest;
EOS and its strategic direction
Multi-site storage, complexity reduction
Computing Centre at CERN
DD - there is an EOS demonstrator
LB - looking for sync with other experiments
BB - need to tackle the situation that WLCG will become relatively less important at sites
FW - we have to make fewer assumptions about what people will do for us.
IB - need to be able to exploit more diverse resources
what's the right level of abstraction?
minimise requirements on storage providers - how?
MJ - remember caches, we will control most storage
first priority - focus on data access paradigms
HSF has data access thing - could simply wait for outcome
- Atlas (MB)
Main themes;
storage evolution
use of object stores, access patterns
beyond x509
going from files to events, streaming models
increased use of tape
network - sharing network intelligence
SDN maybe?
more collaboration on longer term issues
eg exploitation of object stores, also as cache and networks
interested in multi-site storage (but not priority)
ML (joined later)
Focus on network
Getting the DM architecture as flexible as possible (eg to incorporate maximum capacity).
- LHCb (PC)
4x more data after LS2 (so still less than Atlas/CMS today)
Want to to follow trends
On ownershiop of resources - must try to keep ownership of storage as long as possible! Specifically, disk storage. Nearline, not so much... could use commercial providers for cold storage.
Organise storage tech for the resources that we own. Keep diversity low.
Supports forum for storage future (for storage we control)
- CMS (BB)
CMS has functional requirements eg protocol support, performance
hands-off about how storage is run or managed
May evolve CMS to a model comprising caches with various levels of reliability (eviction at T1 is rare but common at T2 for example)
Admit to ourselves that storage is not reliable
beyond that ... layer on top of site storage (eg AAA)
partner with a variety of small projects
may need action on the interfaces, e.g. to support caching operation
FW - We see US universities with more compute power than Fermi or BNL, not part of T2 system, we don't pay them, but we would like to benefit from them. For both CPU and storage. Discussion on caches as latency hiders, and adapting workflows to them.
- WLCG Operations (JA)
Shorter term stuff
Organise storage accounting, continuation of preGDB last year
Increased use of tape - potential fo commonality here, e.g. in monitoring
Topology system - describing a storage object is difficult (this is happening in another group)
Prototypes of impact on operations of these demonstrators
- Xroot (AH)
xrootd is driven by the experiments
Discussion on feasibility of getting experiments to align on a new data delivery model. DD - caching has a good chance of alignment. CMS is happy, let's look at other cases eg Atlas
- dCache (PM)
Support for multi-VO requirements and adoption of industry standards
- France (MJ)
Work on the data model and sync with HSF
- DPM (OK)
Priorites;
space reporting
SRM retirement
caching
-- Next steps
Need at least another iteration before we can start filling preGDB slots and the like. OK to schedule.
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