RAL Tier1 Operations Report for 7th October 2015
Review of Issues during the week 30th September to 7th October 2015.
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- 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.
Resolved Disk Server Issues
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- 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.
Current operational status and issues
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- 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.
Ongoing Disk Server Issues
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- GDSS657 (LHCb_RAW) 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.
Notable Changes made since the last meeting.
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- The Castor Oracle database "pluto" was successfully upgraded to Oracle 11.2.0.3 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 has been 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).
Service
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Scheduled?
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Outage/At Risk
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Start
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End
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Duration
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Reason
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All Castor (All SRMs)
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SCHEDULED
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OUTAGE
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13/10/2015 08:00
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13/10/2015 16:00
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8 hours
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Outage of All Castor instances during upgrade of Oracle back end database.
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All Castor (All SRMs)
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SCHEDULED
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WARNING
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08/10/2015 08:30
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08/10/2015 20:30
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12 hours
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Warning (At Risk) on All Castor instances during upgrade of back end Oracle database.
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Advanced warning for other interventions
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The following items are being discussed and are still to be formally scheduled and announced.
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- 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)
Entries in GOC DB starting since the last report.
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Service
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Scheduled?
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Outage/At Risk
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Start
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End
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Duration
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Reason
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Whole site
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SCHEDULED
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WARNING
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07/10/2015 10:00
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07/10/2015 11:30
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1 hour and 30 minutes
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Warning on site during quarterly UPS/Generator load test.
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All Castor (All SRMs)
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SCHEDULED
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OUTAGE
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06/10/2015 08:00
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06/10/2015 16:00
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8 hours
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Outage of All Castor instances during upgrade of Oracle back end database.
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Whole site
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SCHEDULED
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WARNING
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30/09/2015 07:00
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30/09/2015 09:00
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2 hours
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At Risk during upgrade of network connection from the Tier1 into RAL site core network.
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Open GGUS Tickets (Snapshot during morning of meeting)
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GGUS ID |
Level |
Urgency |
State |
Creation |
Last Update |
VO |
Subject
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116618
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Green
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Top Priority
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On Hold
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2015-10-05
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2015-10-06
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CMS
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PhEDEx DBParam renewal
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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
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30/09/15 |
100 |
100 |
100 |
100 |
100 |
96 |
100 |
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01/10/15 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
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02/10/15 |
100 |
100 |
100 |
62 |
100 |
95 |
100 |
Problem with glexec on new WN configuration when final batch upgraded.
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03/10/15 |
100 |
100 |
100 |
0 |
100 |
96 |
100 |
Continuation of yesterday's problem.
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04/10/15 |
100 |
100 |
100 |
0 |
100 |
98 |
100 |
Continuation of yesterday's problem.
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05/10/15 |
100 |
100 |
100 |
46 |
100 |
98 |
100 |
Continuation of yesterday's problem.
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06/10/15 |
78.3 |
100 |
67 |
58 |
67 |
95 |
100 |
Planned Castor outage for Oracle DB update. (Plus couple of SRM test failures for CMS).
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