Difference between revisions of "Tier1 Operations Report 2016-02-10"

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* GDSS648 (LHCbUser - D1T0) Failed on Tuesday 19th January. Several disks were reporting problems. It was returned to service the following day (20th Jan).
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* GDSS620 (GenTape - D0T1) failed on the first January. The server was returned to service on 1st February. This server had failed on repeat occasions before. Two disks were replaced in the server.
* GDSS732(LHCbDst - D1T0). FSProbe reported problems which suggested a hardware fault on Tuesday 19th January and was taken out of service. One disk was showing a lot of errors. That was replaced and the system returned to service the following day (20th Jan).
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* GDSS682 (AtlasDataDisk - D1T0) failed on Sunday evening (31st Jan). It was returned to service at the end of the afternoon the following day although investigations had failed to find a cause.
* GDSS676 (CMSTape - D0T1). This server was taken out of service on Wednesday (20th Jan). It had been drained of files needing migration following a double disk failure. It was returned to service on Friday 22nd Jan.
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* GDSS620 (GenTape - D0T1) failed on the first January. This server has failed before recently. Investigations ongoing.
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* GDSS667 (AtlasScratchDisk - D1T0) Failed on Monday 18th Jan with a read-only file system. On investigation three disks in the RAID set had problems. Following a lot of work a small number of files were recovered from the server. However, the large majority of the files were declared lost to Atlas.
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* GDSS667 (AtlasScratchDisk - D1T0) Failed on Monday 18th Jan with a read-only file system. On investigation three disks in the RAID set had problems. Following a lot of work a small number of files were recovered from the server. However, the large majority of the files were declared lost to Atlas. The server is re-running the acceptance tests before being put back into service.
 
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Revision as of 21:49, 2 February 2016

RAL Tier1 Operations Report for 3rd February 2016

Review of Issues during the week 27th January to 3rd February 2016.
  • On Friday morning (22nd Jan) there was a problem with the link between the UKLight router and the Tier1 core network. This link is made up of four 10Gbit links. One of these stopped transferring packets in one direction giving intermittent problems that affected data transfers. This was fixed during that morning - the problem having lasted a few hours.
  • We note a significant number of disk server problems over recent weeks/months. Although this last week did not have any disk server failures we have reviewed the situation - particularly looking at one batch of systems which show very high drive failure rates.
  • Significant file loss was reported to Atlas following a triple disk failure on GDSS667 (AtlasScratchDisk - D1T0). A small number (hundreds) of files were successfully recovered from this server - but the majority were lost.
Resolved Disk Server Issues
  • GDSS620 (GenTape - D0T1) failed on the first January. The server was returned to service on 1st February. This server had failed on repeat occasions before. Two disks were replaced in the server.
  • GDSS682 (AtlasDataDisk - D1T0) failed on Sunday evening (31st Jan). It was returned to service at the end of the afternoon the following day although investigations had failed to find a cause.
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.
Ongoing Disk Server Issues
  • GDSS667 (AtlasScratchDisk - D1T0) Failed on Monday 18th Jan with a read-only file system. On investigation three disks in the RAID set had problems. Following a lot of work a small number of files were recovered from the server. However, the large majority of the files were declared lost to Atlas. The server is re-running the acceptance tests before being put back into service.
Notable Changes made since the last meeting.
  • ARC-CE01 was upgraded to version 5.0.5 on Thursday (21st Jan).
Declared in the GOC DB
Service Scheduled? Outage/At Risk Start End Duration Reason
arc-ce04.gridpp.rl.ac.uk SCHEDULED WARNING 01/02/2016 11:00 01/02/2016 12:00 1 hour Upgrade ARC-CE04 to version 5.0.5
arc-ce02.gridpp.rl.ac.uk & arc-ce03.gridpp.rl.ac.uk, SCHEDULED WARNING 28/01/2016 12:00 28/01/2016 13:00 1 hour Upgrading ARC-CE02 & ARC-CE03 to version 5.0.5
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.
  • 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.
  • Fabric
    • Firmware updates on remaining EMC disk arrays (Castor, LFC)
Entries in GOC DB starting since the last report.
Service Scheduled? Outage/At Risk Start End Duration Reason
arc-ce01.gridpp.rl.ac.uk SCHEDULED WARNING 21/01/2016 11:00 21/01/2016 12:00 1 hour Warning during upgrade of this ARC-CE to version 5.0.5.
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
118809 Green Urgent On Hold 2016-01-05 2016-01-13 Towards a recommendation on how to configure memory limits for batch jobs
117683 Green Less Urgent In Progress 2015-11-18 2016-01-05 CASTOR at RAL not publishing GLUE 2
116864 Red Urgent In Progress 2015-10-12 2015-12-16 CMS T1_UK_RAL AAA opening and reading test failing again...
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
20/01/16 100 100 100 100 100 75 100
21/01/16 100 100 100 100 100 93 100
22/01/16 100 100 100 95 96 100 100 Problem on the link between the UKLight router and the Tier1 core.
23/01/16 100 100 100 100 100 68 100
24/01/16 100 100 100 100 100 83 100
25/01/16 100 100 100 100 100 68 100
26/01/16 100 100 100 100 100 100 100


27/01/16 100 100 100 100 100 100 100
28/01/16 100 100 100 100 100 100 100
29/01/16 100 100 100 100 100 100 100
30/01/16 100 100 100 100 100 100 100
31/01/16 100 100 100 100 100 100 100
01/02/16 100 100 100 100 100 100 100
01/02/16 100 100 100 100 100 100 100