Tier1 Operations Report 2015-06-24

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RAL Tier1 Operations Report for 24th June 2015

Review of Issues during the week 17th to 24th June 2015.
  • As reported at the last meeting. AtlasDataDisk in Castor became full on the morning of Wed 17th June. Four additional disk servers were added on Wednesday afternoon (17th) and a further four on Friday (19th). Note that one of the initial set of four servers (GDSS763) failed on the Friday (19th).
  • During last week LHCb reported problems accessing old files in Castor which did not have a stored checksum. (These files have been like this for some years). Stored checksums have been retrospectively added to Castor for these cases.
  • Last Wednesday (17th) following a problem flagged up by LHCb it was realized that we were using incorrect VOMS servers for regenerating the Castor gridmap files. This was fixed that day.
  • A problem transferring files from FNAL to us is being investigated.
  • Yesterday, Tuesday 23rd June, There were two network issues. The first was a spontaneous reboot of a core network switch that led to a break in connectivity to the Tier1 for around 8 minutes. The second was a very high rate of traffic around the Tier1 network that lasted for around 45 minutes from 16:00. This is not completely understood, but appears to have been caused by restarting an old hypervisor and this causing more than one copy of a particular Virtual Machine to run.
Resolved Disk Server Issues
  • GDSS711 (CMSDisk - D1T0) failed on Wednesday evening (17th). The server was checked out but no specific fault found. It was returned to service on Friday (19th).
Current operational status and issues
  • We are running with a single router connecting the Tier1 network to the site network, rather than a resilient pair.
  • The post mortem review of the network incident on the 8th April is being finalised.
  • The intermittent, low-level, load-related packet loss over the OPN to CERN is still being tracked.
Ongoing Disk Server Issues
  • GDSS763 (AtlasDataDisk - D1T0) failed in the early hours of Friday morning (19th June). This was one of the disk servers added to AtlasDataDisk after it became full. After initial checks it was put back in service read-only, but crashed again. The disks have now been placed in a different server/chassis and it is being drained.
Notable Changes made since the last meeting.
  • On Wednesday (just after last week's meeting) a network test was carried out. Thi confirmed that non-Tier1 services on our network now route traffic avoiding our (problematic) Tier1 router pair. The test also coinfirmed the long-standing problem in the primary Tier1 router. This test paves the way for a longer intervention, with the vendor present, to try and get to the bottom of the router problem.
  • Old files in Castor that were missing stored checksums have had these added.
  • Eight additional disk servers have been added to AtlasDataDisk (approaching a Petabyte of extra capacity).
  • The batch job limit for Alice has been completely removed. (It was set at 6000).
  • A detailed change to a database procedure has been made to the LHCb Castor stager (yesterday - Tuesday 23rd) and then to CMS today (Wed 24th). This change significantly speeds up file open times within Castor.
  • Files are being successfull transferred from Durham for Dirac.
Declared in the GOC DB
Service Scheduled? Outage/At Risk Start End Duration Reason
arc-ce05.gridpp.rl.ac.uk SCHEDULED OUTAGE 10/06/2015 12:00 08/07/2015 12:00 28 days, This particular ARC CE will be decommisioned. (Four other ARC CEs remain in production).
Advanced warning for other interventions
The following items are being discussed and are still to be formally scheduled and announced.

Listing by category:

  • Databases:
    • Switch LFC/3D to new Database Infrastructure.
    • Update to Oracle 11.2.0.4. This will affect all services that use Oracle databases: Castor, Atlas Frontier (LFC done)
  • Castor:
    • Update SRMs to new version (includes updating to SL6).
    • Update the Oracle databses behind Castor to version 11.2.0.4. Will require some downtimes (See above)
    • Update disk servers to SL6.
    • Update to Castor version 2.1.15.
  • Networking:
    • Resolve problems with primary Tier1 Router. Need to schedule a roughly half-day outage for the vendor to carry out investigations.
    • Enable the RIP protocol for updating routing tables on the Tier1 routers. (Install patch to Router software).
    • Increase bandwidth of the link from the Tier1 into the RAL internal site network to 40Gbit.
    • Make routing changes to allow the removal of the UKLight Router.
    • Cabling/switch changes to the network in the UPS room to improve resilience.
  • Fabric
    • Firmware updates on remaining EMC disk arrays (Castor, FTS/LFC)
Entries in GOC DB starting since the last report.


Service Scheduled? Outage/At Risk Start End Duration Reason
Whole site SCHEDULED OUTAGE 17/06/2015 13:45 17/06/2015 15:15 1 hour and 30 minutes During this time window there will be a 15 minute disconnection of the RAL-LCG2 site from the network. This will take place sometime between 13:00 - 13:30 UTC. For this 15-minute period all services will be unavailable. The Castor storage system will be stopped at 12:45 UTC before the network break, and restarted once the 15-minute break is over. The declared time window allows time for Castor and other services to be checked out after the network break. The network outage is for a test of a revised network configuration.
srm-atlas.gridpp.rl.ac.uk, UNSCHEDULED WARNING 17/06/2015 10:00 17/06/2015 17:00 7 hours AtlasDataDisk full. Working to resolve this. Other Atlas areas, and reads from AtlasDataDisk are OK.
arc-ce05.gridpp.rl.ac.uk SCHEDULED OUTAGE 10/06/2015 12:00 08/07/2015 12:00 28 days, This particular ARC CE will be decommisioned. (Four other ARC CEs remain in production).
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
114512 Green Less Urgent In Progress 2015-06-12 2015-06-22 Atlas deletion errors for RAL-LCG2
113910 Green Less Urgent Waiting Reply 2015-05-26 2015-06-23 SNO+ RAL data staging
113836 Green Less Urgent In Progress 2015-05-20 2015-06-24 GLUE 1 vs GLUE 2 mismatch in published queues
112721 Red Less Urgent In Progress 2015-03-28 2015-06-23 Atlas RAL-LCG2: SOURCE Failed to get source file size
109694 Red Urgent Waiting Reply 2014-11-03 2015-06-23 SNO+ gfal-copy failing for files at RAL
108944 Red Less Urgent In Progress 2014-10-01 2015-06-16 CMS AAA access test failing at T1_UK_RAL
Availability Report

Key: Atlas HC = Atlas HammerCloud (Queue ANALY_RAL_SL6, Template 508); CMS HC = CMS HammerCloud

Day OPS Alice Atlas CMS LHCb Atlas HC CMS HC Comment
17/06/15 93.8 94.0 50.0 93.0 96.0 96 98 Atlas: DataDiskFull; All: Tests failed during network outage (planned test).
18/06/15 100 100 100 100 100 97 95
19/06/15 100 100 98.0 100 100 93 98 Single SRM Test failure: Could not open connection to srm-atlas
20/06/15 100 100 98.0 100 100 100 100 Single SRM Test failure: Error trying to locate the file in the disk cache
21/06/15 100 100 100 100 100 96 99
22/06/15 100 100 100 100 100 100 100
23/06/15 100 100 100 95.0 100 87 99 SRM and CE test failures during local network problem.