Tier1 Operations Report 2017-05-03

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RAL Tier1 Operations Report for 3rd May 2017

Review of Issues during the week 26th April to 3rd May 2017.
  • LHCb have managed to complete their stripping and merging campaign for data stored at RAL. Nevertheless we still need to follow up with improvements to Castor to resolve throughput and stability issues. The SRMs required a restart on Friday aftternoon (28th April).
  • AtlasDataDisk became full. This severely affected the Atlas SAM tests and hence availability. Investigations show problems with Castor's file deletion rate. Once the disk is full any attempted writes are subsequently cleaned up (- i.e. a delete request). These deletions take all of Castor's capacity to delete files. The result is that once a disk area fills the problem becomes a severe fault and is only resolved by the VO stopping attempts to write data - allowing some level of deletions to happen. However, it is clear that the deletion rate was not sufficient at times before the disk became full - although this is not understood.
  • There was a problem with Castor for CMS overnight last night (Tuesday/Wednesday 25/26 April) when the database reported blocking sessions. This fixed itself after a couple of hours.
  • There is an ongoing problem with one of the argus servers. This has affected CMS CE SAM tests (and hence availability) since yesterday (Tuesday) evening. Work is ongoing at the time of the meeting.
  • We are also seeing a non-negligible failure rate for CE SAM tests for CMS that is not yet understood. CMS are experimented in running with 'lazy download' disabled.
  • There is a problem with the UPS system in the R89 computer problem. Internal capacitors overheated last Friday (28th April) and we are currently running in Mains by-Pass without UPS protection.
Resolved Disk Server Issues
  • GDSS729 (CMSDisk - D1T0) was taken out of service on the 25th April after it became unresponsive. It was returned to service, initially read-only, the following day. A faulty disk drive was found and replaced.
Current operational status and issues
  • We are still seeing a rate of failures of the CMS SAM tests against the SRM. These are affecting our (CMS) availabilities.
Ongoing Disk Server Issues
  • None
Limits on concurrent batch system jobs.
  • CMS Multicore 550
Notable Changes made since the last meeting.
  • Updated GridFTP / XRootD plugins on ECHO Ceph gateways changing the way checksum is stored.
Declared in the GOC DB

None

Advanced warning for other interventions
The following items are being discussed and are still to be formally scheduled and announced.

Pending - but not yet formally announced:

  • Update Castor (including SRMs) to version 2.1.16. Current plan: Central nameserver and LHCb stager on Tuesday 9th May; Atlas and CMS stagers on Thursday 11th May.
  • Update Castor SRMs - CMS & GEN still to do. Problems seen with the SRM update mean these will wait until Castor 2.1.16 is rolled out.

Listing by category:

  • Castor:
    • Update SRMs to new version, including updating to SL6.
    • Update to version 2.1.16
    • Merge AtlasScratchDisk into larger Atlas disk pool.
  • Networking
    • Enable first services on production network with IPv6 now that the addressing scheme has been agreed. (Perfsonar already working over IPv6).
Entries in GOC DB starting since the last report.
  • None
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
128007 Green In Progress 2017-04-20 2017-05-02 CMS T1_UK_RAL, SAM tests failing
127968 Green Less Urgent In Progress 2017-0 2017-0 MICE RAL castor: not able to list directories and copy to
127967 Green Less Urgent On Hold 2017-04-27 2017-04-28 MICE Enabling pilot role for mice VO at RAL-LCG2
127929 Green In Progress In Progress 2017-04-26 2017-04-27 CMS T1_UK_RAL, SAM tests failing
127916 Green Alarm In Progress 2017-04-25 2017-04-25 LHCb RAL srm-s are down again for LHCb
127612 Red Alarm In Progress 2017-04-08 2017-04-10 LHCb CEs at RAL not responding
127598 Green Urgent In Progress 2017-04-07 2017-04-07 CMS UK XRootD Redirector
127597 Green Urgent In Progress 2017-04-07 2017-04-10 CMS Check networking and xrootd RAL-CERN performance
127388 Green Less Urgent In Progress 2017-03-29 2017-05-02 LHCb [FATAL] Connection error for some file
127240 Yellow Urgent In Progress 2017-03-21 2017-04-05 CMS Staging Test at UK_RAL for Run2
126905 Green Less Urgent Waiting Reply 2017-03-02 2017-04-21 solid finish commissioning cvmfs server for solidexperiment.org
124876 Red Less Urgent On Hold 2016-11-07 2017-01-01 OPS [Rod Dashboard] Issue detected : hr.srce.GridFTP-Transfer-ops@gridftp.echo.stfc.ac.uk
117683 Red Less Urgent On Hold 2015-11-18 2017-03-02 CASTOR at RAL not publishing GLUE 2.
Availability Report

Key: Atlas HC = Atlas HammerCloud (Queue ANALY_RAL_SL6, Template 845); Atlas HC ECHO = Atlas ECHO (Template 841);CMS HC = CMS HammerCloud

Day OPS Alice Atlas CMS LHCb Atlas ECHO Atlas HC Atlas HC ECHO CMS HC Comment
26/04/17 100 100 90 82 92 100 22 92 99 All SRM test failures: Atlas - unknown errors. CMS - SRM failures; LHCb - SRM test failures.
27/04/17 100 100 85 86 92 100 51 99 100 All SRM test failures: Atlas - unknown errors. CMS - SRM failures and batch job failures. LHCb - SRM test failures.
28/04/17 100 100 96 81 97 100 93 100 N/A All SRM test failures: Atlas - unknown errors. CMS: SRM test failures. LHCb - SRM test failures.
29/04/17 100 100 85 79 99 100 99 100 N/A All SRM test failures: Atlas - unknown errors. CMS: SRM test failures. LHCb - SRM test failure.
30/04/17 100 100 6 63 100 100 97 100 91 Atlas - disk full. CMS: SRM test failures.
01/05/17 100 100 0 68 96 100 97 100 100 Atlas - disk full. CMS: SRM test failures. LHCb - SRM test failures.
02/05/17 100 100 58 74 96 100 98 98 99 Atlas: SRM test failures as DataDisk full; CMS: CE test failures owing to glexec (argus) problem; LHCb: Single SRM test failure.
Notes from Meeting.
  • None yet