LCG Introduction Kors Bos, NIKHEF, Amsterdam GDB Oct.4, 2006

LCG 2 From the last meeting Minutes of the Sept. meeting at the GDB wiki page – –Comments ? –Thank you Jeremy Coles !! Minutes, Summary and Actions now also on GDB wiki – Actions from Sept meeting: –

LCG 3 Changes and apologies Estonia will join as a CMS Tier-2 site –Mario Kadastik will be at the November GDB meeting Apologies received –Richard Gokieli (Poland) –Roger Jones (UK) –Ruth Pordes (US)

LCG 4 Oct Aud. –Problem with eIRG meeting in Helsinki on Oct.4-5 Nov –Note unusual place: only phone, no vrvs –Possibly pre-GDB meeting on Nov.7 on Storage Classes again Dec IT Aud. Dates for 2006

LCG 5 Oct.18FTS Admin Day at SARA, Amsterdam –Please sign up Oct.24C-RRB meeting at CERN –Closed meeting I don’t claim this to be the full list ! Other Dates for September 2006

LCG 6 GDB meetings in 2007 To avoid confusion in 2007, the GDB is always on the first Wednesday of the month January 10 February 7 March 7 April 4 in Prague May 2 June 6 July 4 August 1 (probably not) August 31 in Vancouver September 5 October 3 November 7 December 5 The CERN IT Auditorium has been reserved those days Decide before the end of 2006

LCG 7 GDB in 2007 Hi Kors, I forgot that I was supposed to contact you about having a GDB meeting at TRIUMF in association with CHEP'07. In talking to Randy Sobie, we thought the following would be good: -- Friday, Aug.31: GDB at TRIUMF -- Saturday/Sunday, Sept. 1-2: LCG (Tier-2) meeting in Victoria -- Sept.3-7: CHEP'07 in Victoria This would mean that people would have to fly in to Vancouver on Thursday. We can arrange for a bus from TRIUMF to the airport after the meeting on Friday so people can get to Victoria easily (30 minute flight). Alternately, we could have the bus drive everyone to Victoria via the ferry, which would be much more scenic. Let me know if this works; we can work out the details later. Cheers, Mike Vetterli

LCG 8 Again and again and again … CERN migration to SLC4 Change to SL4 64-bits needs a new version of VDT Distribution still expected “in October”? 31 st of October? Some LXPLUS and BATCH nodes already on SL4 SLC4 full rollout at CERN still “in the autumn” ? Well planned transition period: –When do the sites change over ? –When do the LHC experiments change over ? –When do we stop the WLCG support for the SL3 version ? –May have different timing for EGEE …

LCG 9 Super Computing 2006 SC06 is in Tampa, Florida Nov – There is a first time EGEE booth CERN participates with CalTech Participating: UK (RAL), FNAL/SLAC, ANL, CalTech/CERN, NL(SARA/NIKHEF), FZK, NDGF(?), EGEE, OSG. Alice/ROOT, who else? New WLCG flyer in the make! WLCG poster?, EGEE poster(s)? IC demo based on Google Earth! Network demo? Mona Lisa? LHCOPN flyer or poster? Shall we set up a mailing list?

LCG 10 Big Files Small files are –Takes more time to transfer (tcp/ip protocol) –Takes more time&space to store, specially on tape –Takes more time&effort to retrieve from tape –You get too many of them … Bigger files are –More appropriate for raw data transfer & storage T0-T1 raw data data distribution –Useful for dataset definition: grouping of files All ESD data belonging to one luminosity record (Atlas) and ESD data goes to all Tier-1’s but also to many Tier-2’s But bigger files are also –More difficult to copy into your (AFS) home directory.. Quota! –More difficult to copy onto your laptop What are the limiting factors? Applications?

LCG 11 Maximum Files sizes File sizes mostly limited to 1 or max 2 GB Reactions to my suggest larger is possible –May be as big as a tape: 200 GB now –May span several tapes: 1TB Not 50 GB yet: ‘leaves too much dead wood’ Increases with increased disk sizes, i.e. time Preferred seems now 10 GB May grow to 50 GB beyond 2010 Is there a plan?

LCG 12 Network test suite OPN will be described by David Foster this afternoon –We know the T0-T1 network and rates quite well –We know the T1-T1 network and rates also well –We know less well the T1-T2 network and rates Design a plan to test T1-T2 connections –E2e routing and bandwidth measurement –The same tool to be used at each site Compare measured bandwidth with requirement Develop a test suite –based of iperf ? –Launched as part of SAM Advice on a solution if there is a problem Action on Don Petravnick, KB, Bruno Hoefft Any help or suggestion much appreciated

LCG 13 Fail-over solutions At least one Tier-1 site is down almost all the time After repair has to take in raw data at twice the rate –Not the best condition to try a new fix If a 10% T1 is down the others could also take 1% more –Assuming there are 11 T1s and they are all equal Requires a ‘democratic’ raw data distribution –True for all experiments? Who distributes the raw data? Experiments or CERN? Relaxes hardware purchases –10% overcapacity OK but factor 2 is ‘expensive’ Rebalancing done at the end of the year

LCG End of Introduction Kors Bos, NIKHEF, Amsterdam GDB Oct.4, 2006