London Tier2 Status

1
London Tier2 Status

• Olivier van der Aa

LT2 Team M. Aggarwal, D. Colling, A. Fage, S.
George, K. Georgiou, W. Hay, P. Kyberd, A.
Martin, G. Mazza, D. McBride, H. Nebrinsky, D.
Rand, G. Rybkine, G. Sciacca, K. Septhon, B. Waugh
2
Outline

• LT2 Usage
• LT2 Sites updates
• LT2 SC4 activity
• Conclusion

3
Number of Running Jobs
January
February
4
Number of running jobs
March
April
5
Number of running jobs
May

• Increase of the infrastructure usage by LHCB last
  month
• Has stressed the system. Caused very slow mds
  responses.

6
Usage and efficiency per VO2006-01-01,2006-04-30

• WallTime consumption
• ATLAS, LHCB, BIOMED, CMS are the top consumers
• Efficiency Fraction of total time which result
  in a successful state.
• Efficiency by order BIOMED, ATLAS, LHCB, CMS.
• Efficiency pattern is notyet understood. Why is
  BIOMED more efficient (ie causes less middleware
  failures)

7
Usage and efficiency per CE 2006-01-01,2006-04-3
0

• WallTime
• QMUL provides 55 of the total WallTime
• Delicate to provide the Service Level Agreement
  of 95 availability of the LT2 with 1FTE at QMUL
• Efficiency
• UCL-CENTRAL the most efficient in job successes
  rate.
• Can be explained because they mainly attract
  biomed jobs

Brunel
8
CE / VO view
Brunel
IC-LESC
Brunel
ucl-central
QMUL
RHUL
IC-HEP
UCL-HEP
ucl-central

• In London we support18 VO. (sixt has not been
  used)
• Right Plots shows the relative VO usage for each
  CE.
• Size of the box is proportional to the total Wall
  Clock Time

9
GridLoad
https//gfe03.hep.ph.ic.ac.uk4175/cgi-bin/load

• Tool to monitor the sites
• -Updates every 5minutes
• -Uses the RTM data and stores it in rrd files
• Shows theNumber of Jobs in any state
• VO view. Stacks the Jobs by VO
• CE view. Stacks the Jobs by CE

• Still a prototype. Will add
• View by GOC and ROC.
• Error checking.
• Add usage (running cpu/total cpu).
• Improve look and feel
• Could interface with NAGIOS for raising alarms
  (high abort rate)

10
GridLoad (cont)

• The GridLoad plots can be useful to spot
  problems.
• Example Observed High Abort rate at one site for
  LHCB jobs
• It helped to be proactive for the VO. Could spot
  that there is a problem before we receive a
  ticket

Aborted Jobs
Running Jobs
11
LT2 Usage Conclusions

• We have now an additional tool to monitor the LT2
  cpu activity on real time.
• The overall usage is increasing.
• We need to understand the efficiency patterns.
  What causes those differences between the VO.
• We need similar real time monitoring tools for
  the storage.

Jan - May
12
Outline

• LT2 Usage
• LT2 Sites updates
• LT2 SC4 activity
• Conclusion

13
Brunel site update

• New Cluster provided by Streamline Computing
• Supermicro dual processor dual core AMD Opteron
  nodes
• 40x1.8 GHz, 4GB memory, 80 GB disk
• Head node 2 GHz 8GB memry, 320 GB disk
• Total 164 Cores
• Is in the process of being configured
• Gb connection ?
• 1Gb wan at Brunel in 65 days from now.
• They are currently buying appropriates switches
  and related hardware.
• Will have a throttling router that limits the LCG
  traffic if the university demand is high. If the
  university demand is low then the LCG will have
  higher allocation
• The Brunel site is expected to have a 10 times
  faster connection (200Mb) by September.
• SRM
• best rate was 59Mb/s .
• Will remove any nfs mounted filesystem. No real
  showstopper there.

14
IC Sites update

• HEP
• Old IBM (60CPU) cluster running smoothly, almost
  full of jobs for the last two month.
• Will build a new cluster with off the shelf boxes
• 40 Dual Core AMD
• 40 TB of disk (non raid)
• Will use SGE for the job manager.

15
IC Sites update

• Investigated FTS performance issues with
  dCachelt-gtdCache transfers
• FTS using urlcopy causes high iowait

iowait
FTS/urlcopy (130Mb/s)
FTS/srmcp (179Mb/s)
Block
Block
Time
Time
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IC Sites update

• LESC
• 33 of 400 1.8 GHz opterons.
• Running RHEL3 64 bit.
• SGE job manager.
• DPM storage with small disk partition
• Currently porting DPM to SOLARIS to avoid nfs
  mounting file systems used for the SRM.
• See the progressing work at http//www.gridpp.ac.u
  k/wiki/DPM-on-Solaris
• Difficulties Improving usage. Several VO not
  comfortable with 64bit arch even if 32 bit
  libraries are there
• ICT
• Deploying a new 200 Xeon cluster running PBS for
  College Use.
• Will have a share of 30 in that cluster for LCG
• 30TB of raid storage that will be shared.
• Difficulties They want to use GT 3.2.1

17
QMUL site update

• Lots of activity with the commissioning of their
  new cluster provided by Viglen
• 280 Dual Core Opterons (270) 2GHz
• All nodes have 2x250 Gb disks 140TB !
• What filesystem to use with that environment.
  Will consider lustre.
• All nodes are 1Gb connected. With 10Gb inter
  switch links.
• Now online with 1600 job slots
• Problems
• Site stability under high job load nfs mounted
  software area not coping
• Raid boxes giving hardware errors. Seemed to be
  due to loose sata connectors. The disks where
  tested ok with smart. Not yet clear what it is
  due to.
• Reliability of DPM on Poolfs

18
UCL sites update

• CCC
• Have successfully moved to SGE job manager to
  service364 Slots (91 dual cpu hyper threading)
• Improved their SRM performance by using direct
  fiberchannel link to the raid array from the head
  node.
• Write bandwidth moved from 90Mb/s to 238Mb/s
• Will have 40 additional nodes (160 slots) soon.
• Moving their cluster from one building to another
  one will start on July 3 for 1 week.
• HEP
• New Gb switches have been bought. Need to cable
  them to the head node.
• Will have 1,2 boxes with mirrored 120Gb disks
  with dpm pool installed on them to support non
  Atlas vo
• Atlas will still be using nfs mounted
• Problem Performance for Atlas storage

19
RHUL siteupdate

• Cluster running smoothly
• 142 Job slots almost full for two month. All VO
  targetting that site.
• No more nfs mounted disks with write access from
  DPM .
• Broad VO usage
• Update on the 1Gb connection
• Purchase order was signed yesterday.
• Discussions are now starting as to when it will
  be installed.
• Problems
• Need to be able to drain Pool to remove the
  read-only nfs mounted filesystem

20
Transfers throughput status
  Rate (Mb/s) Rate (Mb/s)  
Site Inbound Outbound Update
Brunel 57 59 Gb connection signed (200Mb by september)
IC-HEP 80 190 FTS performance problem not yet understood
IC-LeSC 156 95 DPM being build for solaris
QMUL 118 172 Poolfs need to be recompiled with round robin feature
RHUL 59 58 Gb connection signed
UCL-HEP 71 63 Gb switches there.
UCL-CENTRAL 90 309 Move to direct fiberchannel connection. Rate is now 238Mb/s
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Outline

• LT2 Usage
• LT2 Sites updates
• LT2 SC4 activity
• Conclusion

22
SC4 Activity

• CMS Target is CSA06 (Computing Software and
  Analysis Challenge)
• CSA06 ObjectiveA 50 million event exercise to
  test the workflow and dataflow associated with
  the data handling and data access model of CMS
• Will test the new cms reconstruction framework
  for large production
• Need 20MB/s bandwidth to T2 storage
• Will start on 15 Sept
• More information can be found athttps//twiki.ce
  rn.ch/twiki/bin/view/CMS/CSA06
• IC-HEP and IC-LESC preparing for CSA06
• Strategy is to help other sites when IC is ok.
• New PheDex installed that uses FTS
• Need to solve the FTS performance issues
• ProdAgent configuration prepared for IC-LESC and
  IC-HEP
• Brunel Involved in PheDex.
• ATLAS
• No commitment yet.

23
Conclusions

• Real Time monitoring of the LT2 job states in
  place
• The usage is increasing
• Site evolution
• SGE deployed at UCL-CENTRAL
• QMUL more than doubled the number of job slots
• Brunel Gb connection on the right track,
  Commissioning a new cluster (160 cores)
• IC spotted FTS performance issues, Porting of
  DPM under solaris ongoing, Will commission a new
  cluster at HEP
• RHUL very stable site, Gb connection signed.
• General storage evolution In the process of
  removing nfs mounts.
• SC4 Involvement in the CMS SC4 activity is going
  on. Need to have a volunteer in the atlas sc4.

24
LT2
Thanks to all of the Team M.
Aggarwal, D. Colling, A. Fage, S. George, K.
Georgiou, M. Green, W. Hay, P. Hobson, P. Kyberd,
A. Martin, G. Mazza, D. McBride, H. Nebrinsky, D.
Rand, G. Rybkine, G. Sciacca, K. Septhon, B.
Waugh,