Difference between revisions of "Tier1 Operations Report 2016-01-27"

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| style="background-color: #b7f1ce; border-bottom: 1px solid silver; text-align: center; font-size: 1em; font-weight: bold; margin-top: 0; margin-bottom: 0; padding-top: 0.1em; padding-bottom: 0.1em;" | Review of Issues during the week 20th to 27th January 2016.
 
| style="background-color: #b7f1ce; border-bottom: 1px solid silver; text-align: center; font-size: 1em; font-weight: bold; margin-top: 0; margin-bottom: 0; padding-top: 0.1em; padding-bottom: 0.1em;" | Review of Issues during the week 20th to 27th January 2016.
 
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−
* As reported last week the CMSTape system has been busy - and throughput was compromised by two out of its five disk servers being out of service at the start of last week. An extra disk server was added on Friday (15th Jan). There was also a problem with CMS tests as test files flushed off the disk cache - and took a very long time (some days) to re-recall them from tape.
+
* 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.
+
* 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.
 
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| style="background-color: #f8d6a9; border-bottom: 1px solid silver; text-align: center; font-size: 1em; font-weight: bold; margin-top: 0; margin-bottom: 0; padding-top: 0.1em; padding-bottom: 0.1em;" | Resolved Disk Server Issues
 
| style="background-color: #f8d6a9; border-bottom: 1px solid silver; text-align: center; font-size: 1em; font-weight: bold; margin-top: 0; margin-bottom: 0; padding-top: 0.1em; padding-bottom: 0.1em;" | Resolved Disk Server Issues
 
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−
* GDSS677 (CMSTape - D0T1) was taken out of service having had a double disk failure on Monday (11th Jan). Following the first rebuild a another problematic disk was found and the system was returned to service on Monday (18th Jan) once that too had been resolved.
+
* GDSS648 (LHCbUser - D1T0) Failed on Tuesday 19th January. Several disks were reporting problems. It was returned to service the following day (20th Jan).
 +
* 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).
 +
* 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.
 
* GDSS620 (GenTape - D0T1) failed on the first January. This server has failed before recently. Investigations ongoing.
−
* GDSS667 (AtlasScratchDisk - D1T0) called out in teh early hours of Monday 18th Jan with a read-only file system. On investigation three disks in the RAID set had problems. Work has been continuing to try and fix this but it is looking difficult.
+
* 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.
−
* GDSS648 (LHCbUser - D1T0) Failed yesterday morning (19th January). Still under investigation.
+
−
* GDSS732(LHCbDst - D1T0). FSProbe reported problems which suggests hardware fault yesterday afternoon (19th Jan). Taken out of service and undergoing investigations.
+
−
* GDSS676 (CMSTape - D0T1). Double disk failure seen yesterday. Server drained of files needing migration and then taken out of service this morning (20th Jan) to allow the first disk to rebuild.
+
 
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−
* One additional disk server added to CMSTape.
+
* ARC-CE01 was upgraded to version 5.0.5 on Thursday (21st Jan).
−
* Pilot role accounts and other set-up completed for the support of T2K & NA62 via GridPP Dirac.
+
 
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* None
+
{| border=1 align=center
 +
|- bgcolor="#7c8aaf"
 +
! 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
 +
|}
 
<!-- **********************End GOC DB Entries************************** ----->
 
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** Migration of data from T10KC to T10KD tapes (affects Atlas & LHCb data).
 
** Migration of data from T10KC to T10KD tapes (affects Atlas & LHCb data).
 
* Networking:
 
* Networking:
−
** Make routing changes to allow the removal of the UKLight Router.
+
** Replace the UKLight Router.
 
* Fabric
 
* Fabric
 
** Firmware updates on remaining EMC disk arrays (Castor, LFC)
 
** Firmware updates on remaining EMC disk arrays (Castor, LFC)

Latest revision as of 10:02, 27 January 2016

RAL Tier1 Operations Report for 20th January 2016

Review of Issues during the week 20th to 27th January 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
  • GDSS648 (LHCbUser - D1T0) Failed on Tuesday 19th January. Several disks were reporting problems. It was returned to service the following day (20th Jan).
  • 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).
  • 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.
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
  • GDSS620 (GenTape - D0T1) failed on the first January. This server has failed before recently. Investigations ongoing.
  • 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.
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 67 100
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