Difference between revisions of "Tier1 Operations Report 2016-10-26"

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* There have been some problems over the last fortnight with load on AtlasScratch in Castor. (This did not affect other areas in Castor). The number of Atlas Pilot jobs has been reduced, and then increased, at various times to limit the load on Castor. The weighting of gridftp jobs on atlasScratchDisk within Castor was changed on 10th Oct to increase the job capacity.
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* The main issue this week has been the security announcement CVE-2016-5195. In response a number of services were stopped. In essence we stopped the batch system on Monday (24th Oct). Storage (Castor) was able to continue running. At the time of the meeting we are testing the patch.
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* There have also been load problems on the Castor GEN instance. These have been caused by a large number of accesses from jobs running at other sites by a particular ILC user. This has affected other VOs access to Castor (for example ALICE). We are in contact with the user to tackle this.
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* There was a recurrence of the problem with the squids on Wednesday evening (19th Oct). This had a knock-on effect on CVMFS clients on the batch worker nodes and for a while reduced the number of worker nodes available to start jobs.
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* There was a problem with the squids on Friday (14th Oct). The problem was in the Atlas Frontier system. However, as the squids are multiple-use this had a knock-on effect on CVMFS clients on the batch worker nodes.
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Revision as of 10:31, 26 October 2016

RAL Tier1 Operations Report for 26th October 2016

Review of Issues during the week 19th to 26th October 2016.
  • The main issue this week has been the security announcement CVE-2016-5195. In response a number of services were stopped. In essence we stopped the batch system on Monday (24th Oct). Storage (Castor) was able to continue running. At the time of the meeting we are testing the patch.
  • There was a recurrence of the problem with the squids on Wednesday evening (19th Oct). This had a knock-on effect on CVMFS clients on the batch worker nodes and for a while reduced the number of worker nodes available to start jobs.
Resolved Disk Server Issues
  • GDSS648 (LHCbUser - D1T0) failed on Saturday evening (15th Oct). It is showing both disk and network problems. It was finally returned to service on Tuesday 25th Oct.
  • GDSS699 (LHCbDst - D1T0) failed on Saturday (22nd Oct). It was returned to service later that day read-only. On Monday (23rd) it was taken down for further investigation - being put back in service again the following day.
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.
  • The intermittent, low-level, load-related packet loss that has been seen over external connections is still being tracked. The replacement of the UKLight router appears to have reduced this - but we are allowing more time to pass before drawing any conclusions.
Ongoing Disk Server Issues
  • GDSS896 (CMSTape - D0T1) was taken out of service yesterday (25th Oct) to investigate memory errors.
Notable Changes made since the last meeting.
  • On Wednesday 5th October the UKLight Router was replaced. This has also enabled a a 40 GBit connection to the RAL border routers (i.e. giving a datapath of up to 40Gbit for the bypass connection.) We have seen a significant increase in traffic over the bypass route since this change - well exceeding the previous 10Gbit limit.
  • Some re-balancing of the disk servers in lhcbDst has been carried out following a problem where some became full.
  • Some changes were made to increase the number of CMS batch jobs that we run in order to bring the number more into line with the pledge. This was both an increase in the number of worker nodes draining at any time (from 10 to 20) to allow more multi-core jobs (CMS' jobs are purely multicore) as well as an increase in the limit in Condor.
Declared in the GOC DB
Service Scheduled? Outage/At Risk Start End Duration Reason
All Castor Tape. SCHEDULED WARNING 01/11/2016 07:00 01/11/2016 16:00 9 hours Tape Library not available during work on the mechanics. Tape access for read will stop. Writes will be buffered on disk and flushed to tape after the work has completed.
arc-ce01, arc-ce02, arc-ce03, arc-ce04, lcgvo07, lcgvo08, lcgwms04, lcgwms05 UNSCHEDULED OUTAGE 24/10/2016 15:32 28/10/2016 13:00 3 days, 21 hours and 28 minutes EGI-SVG-CVE-2016-5195, vulnerability handling in progress
arc-ce01, gridftp.echo.stfc.ac.uk, ip6tb-ps01, ip6tb-ps01, lcgps01, lcgps02, s3.echo.stfc.ac.uk, vacuum.gridpp.rl.ac.uk, xrootd.echo.stfc.ac.uk, UNSCHEDULED OUTAGE 24/10/2016 15:00 28/10/2016 12:00 3 days, 21 hours EGI-SVG-CVE-2016-5195, vulnerability handling in progress
Advanced warning for other interventions
The following items are being discussed and are still to be formally scheduled and announced.

Listing by category:

  • Castor:
    • Update to Castor version 2.1.15. Planning to roll out January 2017. (Proposed dates: 10th Jan: Nameserver; 17th Jan: First stager (LHCb); 24th Jan: Stager (Atlas); 26th Jan: Stager (GEN); 31st Jan: Final stager (CMS)).
    • Update SRMs to new version, including updating to SL6. This will be done after the Castor 2.1.15 update.
    • Migration of LHCb data from T10KC to T10KD tapes. The additional 'D' tape drives ave been delivered. We await installation into the tape library by the vendor.
  • Fabric
    • Firmware updates on older disk servers.
Entries in GOC DB starting since the last report.
Service Scheduled? Outage/At Risk Start End Duration Reason
arc-ce01, arc-ce02, arc-ce03, arc-ce04, lcgvo07, lcgvo08, lcgwms04, lcgwms05 UNSCHEDULED OUTAGE 24/10/2016 15:32 28/10/2016 13:00 3 days, 21 hours and 28 minutes EGI-SVG-CVE-2016-5195, vulnerability handling in progress
arc-ce01, gridftp.echo.stfc.ac.uk, ip6tb-ps01, ip6tb-ps01, lcgps01, lcgps02, s3.echo.stfc.ac.uk, vacuum.gridpp.rl.ac.uk, xrootd.echo.stfc.ac.uk, UNSCHEDULED OUTAGE 24/10/2016 15:00 28/10/2016 12:00 3 days, 21 hours EGI-SVG-CVE-2016-5195, vulnerability handling in progress
Open GGUS Tickets (Snapshot during morning of meeting)
GGUS ID Level Urgency State Creation Last Update VO Subject
124188 Green Less Urgent In Progress 2016-10-03 2016-10-03 Atlas UK Lpad-RAL-LCG224 : Frontier squid down
123504 Yellow Less Urgent Waiting for Reply 2016-08-19 2016-09-20 T2K proxy expiration
122827 Green Less Urgent Waiting for Reply 2016-07-12 2016-09-14 SNO+ Disk area at RAL
121687 Red Less Urgent On Hold 2016-05-20 2016-09-30 packet loss problems seen on RAL-LCG perfsonar
120350 Yellow Less Urgent On Hold 2016-03-22 2016-08-09 LSST Enable LSST at RAL
117683 Amber Less Urgent On Hold 2015-11-18 2016-04-05 CASTOR at RAL not publishing GLUE 2 (Updated. There are ongoing discussions with GLUE & WLCG)
Availability Report

Key: Atlas HC = Atlas HammerCloud (Queue ANALY_RAL_SL6, Template 729); CMS HC = CMS HammerCloud

Day OPS Alice Atlas CMS LHCb Atlas HC CMS HC Comment
19/10/16 100 100 100 98 100 N/A N/A Single SRM test failure because of a user timeout error
20/10/16 100 100 100 98 100 N/A N/A Single SRM test failure because of a user timeout error
21/10/16 100 100 100 98 100 N/A N/A Single SRM test failure because of a user timeout error
22/10/16 100 100 100 100 100 N/A 100
23/10/16 100 100 100 100 100 N/A N/A
24/10/16 0 100 100 63 100 N/A N/A Systems (especially batch) down for CVE-2016-5195
25/10/16 0 57 56 0 57 N/A N/A Systems (especially batch) down for CVE-2016-5195
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