Difference between revisions of "Tier1 Operations Report 2015-10-07"

Latest revision as of 14:55, 8 October 2015

RAL Tier1 Operations Report for 7th October 2015

• There was a problem running batch jobs that make use of glexec over the weekend. This was traced to a missing component on the new worker node configuration. This caused a very large loss of availability for CMS. How this problem did not become apparent until the final batch of worker nodes was upgraded has not yet been understood.
• We have been working to understand the remaining low level of packet loss seen within a part of our Tier1 network. Some housekeeping tasks have been carried out as part of this.
• LHCb have reported an ongoing low but persistent rate of failure when copying the results of batch jobs to other sites. They have also reported a current problem that sometimes occurs when writing these files to our Castor storage.

• GDSS636 and GDSS637 (AtlasTape - D0T1) were both taken out of service for a time on Saturday (3rd Oct). Tests were failing against these machines but subsequent analysis showed they were just suffering extremely high load so they were returned to service.

• The intermittent, low-level, load-related packet loss seen over external connections is still being tracked.
• Long-standing CMS issues. The two items that remain are CMS Xroot (AAA) redirection and file open times. Work is ongoing into the Xroot redirection with a new server having been added in recent weeks. File open times using Xroot remain slow but this is a less significant problem.

• GDSS657 (LHCb_RAW - D0T1) failed on Saturday (3rd October). After being checked it was returned to service the following day in read-only mode. However, investigations to fix a problem on this server (failed battery on the RAID card) during yesterday's Castor outage uncovered a further problem and the server has been kept out of service. There are no files on the server awaiting migration - so it has no impact on access to LHCb files. Four files were found to be corrupt (partially written) from the time when the server first failed and these have been reported to LHCb.

• The Castor Oracle database "pluto" was successfully upgraded to Oracle 11.2.0.4 yesterday (6th Oct).
• Some internal housekeeping on the Tier1 network has taken place. This has mainly been adding in some second network links where this had been previously configured.
• The final batch of worker nodes is being updated to the new configuration making use of CVMFS to pick up grid middleware.
• There was a successful UPS/Generator load test this morning (Wed. 7th Oct).

• Upgrade of remaining Castor disk servers (those in tape-backed service classes) to SL6. This will be transparent to users.
• Complete the upgrade of the Oracle databases behind Castor to version 11.2.0.4. The first steps of this multi-step upgrade has been carried out. Further dates are declared in the GOC DB with an 'at risk' on Castor tomorrow and then a shorter outage of Castor next Tuesday (13th October).
• Some detailed internal network re-configurations to enable the removal of the old 'core' switch from our network. This includes changing the way the UKLIGHT router connects into the Tier1 network.

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:
  • Make routing changes to allow the removal of the UKLight Router.
• Fabric
  • Firmware updates on remaining EMC disk arrays (Castor, LFC)

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