Tier1 Operations Report 2015-08-26

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RAL Tier1 Operations Report for 26th August 2015

Review of Issues during the week 19th to 26th August 2015.
  • Last week we reported a significant backlog of migrations to tape for Atlas as the instance was seeing very high load. Castor caught up with the backlog overnight Thursday/Friday (21/21 Aug) - and there have been no problems since then.
Resolved Disk Server Issues
  • GDSS720 (AtlasDataDisk - D1T0) crashed on Tuesday 11th. The machine is put back in draining mode on the 12th. Drain still ongoing ahead of further investigations.
  • GDSS707 (AtlasDataDisk - D1T0) crashed on the morning of Monday 17th Aug. The server has been put back in service readonly. It will be drained for further intervention once the drain of GDSS720 is complete.
Current operational status and issues
  • As reported last week the post mortem review of the network incident on the 8th April has been finalised. It can be seen here:
  • The intermittent, low-level, load-related packet loss over the OPN to CERN is still being tracked. An attempoed fix (peplacing the cables between the Tier1 core network and the UKLight router) had no effect.
  • There are some on-going issues for CMS. These are a problem with the Xroot (AAA) redirection accessing Castor; Slow file open times using Xroot. The poor batch job efficiencies have been improved since a change to the Linux I/O scheduler on CMS disk servers.
Ongoing Disk Server Issues
  • None
Notable Changes made since the last meeting.
  • The rollout of the new worker node configuration continues. Around a quarter of the batch farm has now been upgraded.
  • The network link between the Tier1 core network and the UKLight router was switched to a new pair of fibres.
Declared in the GOC DB
Service Scheduled? Outage/At Risk Start End Duration Reason
Castor Atlas & GEN instances. SCHEDULED OUTAGE 13/10/2015 08:00 13/10/2015 16:00 8 hours Outage of All Castor instances during upgrade of Oracle back end database.
All Castor SCHEDULED WARNING 08/10/2015 08:30 08/10/2015 20:30 12 hours Warning (At Risk) on All Castor instances during upgrade of back end Oracle database.
All Castor SCHEDULED OUTAGE 06/10/2015 08:00 06/10/2015 20:30 12 hours and 30 minutes Outage of All Castor instances during upgrade of Oracle back end database.
Castor Atlas & GEN instances. SCHEDULED WARNING 22/09/2015 08:30 22/09/2015 20:30 12 hours Warning (At Risk) on Atlas and GEN Castor instances during upgrade of back end Oracle database.
Castor Atlas & GEN instances. SCHEDULED OUTAGE 15/09/2015 08:00 15/09/2015 20:30 12 hours and 30 minutes Outage of Atlas and GEN Castor instances during upgrade of Oracle back end database.
Whole Site SCHEDULED WARNING 03/09/2015 08:25 03/09/2015 09:25 1 hour At risk on site during brief network re-configuration. Actual change expected at 07:30 (UTC).
All Castor Disk Only Service Classes. SCHEDULED WARNING 27/08/2015 09:30 27/08/2015 19:00 9 hours and 30 minutes Warning on Castor Disk Storage as servers upgraded to SL6. This is a rolling update of the servers - and each is expected to be unavailable for around 30 minutes during the upgrade. (Continuation of rolling upgrade from previous day).
All Castor Disk Only Service Classes. SCHEDULED WARNING 26/08/2015 09:30 26/08/2015 18:00 8 hours and 30 minutes Warning on Castor Disk Storage as servers upgraded to SL6. This is a rolling update of the servers - and each is expected to be unavailable for around 30 minutes during the upgrade.
Advanced warning for other interventions
The following items are being discussed and are still to be formally scheduled and announced.
  • Upgrade of Castor disk servers to SL6. For the D1T0 Service Classes this is being done today/tomorrow (26/27 August) with an extended 'At Risk'. (Declared in GOC DB)
  • Upgrade of the Oracle databases behind Castor to version 11.2.0.4. This is a multi-step intervention. Dates declared in GOC DB (See above).
  • Some detailed internal network reconfigurations to be tackled now that the routers are stable. Notably:
    • Brief (less than 20 seconds) break in internal connectivity while systems in the UPS room are re-connected. (3rd Sep.)
    • Replacement of cables and connectivity to the UKLIGHT router that provides our link to both the OPN Link to CERN and the bypass route for other data transfers.
  • Extending the rollout of the new worker node configuration.

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 databases behind Castor to version 11.2.0.4. Will require some downtimes (See above)
    • Update disk servers to SL6 (ongoing)
    • Update to Castor version 2.1.15.
  • Networking:
    • 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
All Castor disk-only service classes. SCHEDULED WARNING 26/08/2015 09:30 26/08/2015 18:00 8 hours and 30 minutes Warning on Castor Disk Storage as servers upgraded to SL6. This is a rolling update of the servers - and each is expected to be unavailable for around 30 minutes during the upgrade.
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
115805 Green Less Urgent In progress 2015-08-21 2015-08-21 SNO+ RAL WMS logs
115573 Green Urgent In progress 2015-08-07 2015-08-26 CMS T1_UK_RAL Consistency Check (August 2015)
115434 Green Less Urgent In progress 2015-08-03 2015-08-07 SNO+ glite-wms-job-status warning
115290 Green Less Urgent On Hold 2015-07-28 2015-07-29 FTS3@RAL: missing proper host names in subjectAltName of FTS agent nodes
108944 Red Less Urgent In Progress 2014-10-01 2015-08-17 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
19/08/15 100 100 100 100 100 98 100
20/08/15 100 100 100 100 100 97 100
21/08/15 100 100 100 100 100 86 96
22/08/15 100 100 100 100 100 98 100
23/08/15 100 100 100 100 100 94 n/a
24/08/15 100 100 100 100 100 94 100
25/08/15 100 95.0 98.0 100 100 97 98 Alice: Single ARC CE test failure; Atlas: Single SRM test failure.