QoS

The WG

Given the expected flat budget for High-Lumi / RUN 4, the group will explore mechanisms for cost savings through promoting a diversity in the options available to sites for their storage provision. By introducing a new consideration, "Quality of Service", sites could drive down the total cost of storage while allowing experiments to optimise their usage.

Read more about this in our mandate.

QoS

A Storage QoS represents a common agreement between storage providers and the scientists using that storage on how that storage system should behave. A QoS class is typically understood in terms of access-latency, bandwidth, likelihood of data loss.

Some storage systems may provide a single QoS, while others may provide several QoS.

Data may require different QoS classes at different times. Moving away from simple descriptions (DISK and TAPE) to more general concepts may allow sites to provide that storage in new and innovative ways that drive down cost. It may also allows trade-offs, such as providing increased storage capacity but with an increased risk of data loss.

Current Activities

Phone conferences - https://indico.cern.ch/category/10831/

QoS White Paper

The WG has published a white paper describing QoS and its potential for WLCG.

Site survey

We have conducted a survey WLCG sites so that we can learn what directions relevant to QoS are currently being explored.

Questions, answers and conclusions are available at QoSSurveyAnswers

Support in WLCG storage systems

We are compiling an overview of current and planned support for QoS concepts in WLCG storage systems.

The document is available here.

Participating in the group

We can be reached at wlcg-doma-qos@cernNOSPAMPLEASE.ch.

All are welcome to join the WG - https://e-groups.cern.ch/e-groups/EgroupsSubscription.do?egroupName=wlcg-doma-qos

Experiment involvement

We are coordinating our development work with various WLCG experiments to come up with a common understanding how QoS may be used.

To facilitate this, we have (or aim to have) a specific contact person for each VO.

ATLAS: Mario Lassnig

CMS: Position vacant

LHCb: Christophe Haen

Alice: Nikola Hardi

Technology/Software involvement

Rucio: Martin Barisits

gfal/FTS: Edward Karavakis

xrootd: Position vacant

EOS: Mihai Patrascoiu

CTA: Oliver Keeble

dCache: Paul Millar

DPM: Oliver Keeble