fts & srm

hepsysman 2005 Storage MiddlewareJens G JensenCCLRC/RAL

FTS & SRM

[email protected] Oxford

5 Dec 2005


What is FTS

• EGEE JRA1 File Transfer Service• Reliable file transfer

– Manages talking to Storage Elements (via SRM interface)

– Manages GridFTP (third party) data transfers between SEs

– Restarts in case of failure


Catalogues and Names and Stuff

Confusingly(?) many names for files:

•LFN: Logical File Name

•GUID: used by RM•SFN: Site filename

–née PFN – “physical”

•SURL: SFN as URL•StFN: Storage file name

•TURL: Transfer URL

Replicamanager

Replicacatalogue

StorageElement

MassStorage

User

SEdisk cache

LFN

GUIDSURL

TURL

StFN

SFN


Why FTS

• Many SRM 2.1 implementations are new– Interoperability problems expected– Not all sites will upgrade from 1.1 at same

time• In the interim phase, FTS can speak to

all flavours of SRM– Until all SRMs have 2.1 interface and can

interoperate• Uses put/get between SRMs


Plans for FTS

• Support for SRM 2.1 “by end of 2005”– According to Peter Kunszt– However, plan says not till version 1.6?

• Will speak to all SRMs• Am I speaking to 1.1 or 2.1.1-

something?1. Use service discovery2. Try – and be resilient to failure3. Fetch SRM metadata


Plans for FTS

• FTS will not use advanced features– At least in near future (<= EGEE_1)– Pinning, space reservation


Goals for FTS

• See later talk for SC4 goals• Read about Chris’ experiences:

http://wiki.gridpp.ac.uk/wiki/RALPP_Local_SC4_Preparations

• And the FTS pages in the Wiki– http://wiki.gridpp.ac.uk/wiki/FTS

• phedex will (can?) move files via FTS


Issues

• Abysmal performance FTSing files out of dCache – OK with DPM – Investigations ongoing…– Doesn’t look like an FTS problem

• Will FTS meet the deadline for 2.1 support?– Important (critical?) dependency for our

goals

fts & srm

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