Tier1 Operations Report 2016-03-30

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RAL Tier1 Operations Report for 30th March 2016

Review of Issues during the week 16th to 23rd March 2016.
  • Security updates have been rolled out. There an outage of Castor last Thursday during which all the component servers were successfully updated and rebooted within the announced downtime. During this time job starts were blocked on the batch farm. Various batch farm nodes (Condor masters etc) were also rebooted at this time and there was a confusion that led to batch jobs not being re-allowed to start until later that evening.
Resolved Disk Server Issues
  • None
Current operational status and issues
  • There is a problem seen by LHCb of a low but persistent rate of failure when copying the results of batch jobs to Castor. There is also a further problem that sometimes occurs when these (failed) writes are attempted to storage at other sites. A recent modification has improved, but not completed fixed this.
  • The intermittent, low-level, load-related packet loss seen over external connections is still being tracked. Likewise we have been working to understand some remaining low level of packet loss seen within a part of our Tier1 network.
  • The draining of Castor disk servers is very slow. We need to drain a few old servers to provide spares - this being part of the deployment plan and server lifecycle. This does not yet impact services but is being followed up.
Ongoing Disk Server Issues
  • GDSS620 (GenTape - D0T1) Reported a read-only file system on the 15th March and was taken out of production. Two T2K files that were not yet copied to tape were corrupt and have been reported as lost. Work still ongoing.
Notable Changes made since the last meeting.
  • Firmware updates were carried out on Monday (21st) on the RAID cards in the "Clustervision '11" batch of worker nodes that are in D1T0 service classes.
  • Patching and rebooting for security updates.
  • A load balancer has been brought partly into service in front of the Test FTS3 instance.
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.
  • The Castor 2.1.15 update is pending. Testing has shown a database related performance issue which is being followed up. We await successful resolution of that problem and completion of testing before scheduling.
  • Decommissioning of "GEN Scratch" storage in Castor.

Listing by category:

  • Databases:
    • Switch LFC/3D to new Database Infrastructure.
  • Castor:
    • Update SRMs to new version (includes updating to SL6).
    • Update to Castor version 2.1.15.
    • Migration of data from T10KC to T10KD tapes (affects Atlas & LHCb data).
  • Networking:
    • Replace the UKLight Router. Then upgrade the 'bypass' link to the RAL border routers to 2*10Gbit.
  • Fabric
    • Firmware updates on remaining EMC disk arrays (Castor, LFC)
  • Grid Services
    • A Load Balancer (HAProxy) will be used in front of the FTS service.
Entries in GOC DB starting since the last report.
Service Scheduled? Outage/At Risk Start End Duration Reason
Whole Site UNSCHEDULED WARNING 29/03/2016 21:50 30/03/2016 11:00 13 hours and 10 minutes Network problem fixed. Site contactable and services now available. Putting site in warning overnight.
Whole site UNSCHEDULED OUTAGE 29/03/2016 19:00 29/03/2016 21:46 2 hours and 46 minutes Network problem casuing site to be unavailable. Cause as yet unknown.
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
120350 Green Less Urgent In Progress 2016-03-22 2016-03-22 LSST Enable LSST at RAL
119841 Green Less Urgent In Progress 2016-03-01 2016-03-22 LHCb HTTP support for lcgcadm04.gridpp.rl.ac.uk
117683 Green Less Urgent In Progress 2015-11-18 2016-02-17 CASTOR at RAL not publishing GLUE 2
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
23/03/16 100 100 100 100 100 98 100
24/03/16 100 100 100 85 92 94 100 Network problem (Partial failure of one of four links to UKLight router).
25/03/16 100 100 61 49 88 N/A 100 Continuation of above.
26/03/16 100 100 100 100 96 N/A N/A Single SRM Test failure. [SRM_INVALID_PATH] No such file or directory
27/03/16 100 100 66 55 100 N/A 100 Problem with test submission affecting many Atlas & CMS sites.
28/03/16 100 100 100 100 100 N/A 100
29/03/16 89.6 100 100 85 90 N/A 90 Network problem. (Problem with one of RAL border routers. Tier1 Router pair didn't fail over).