RAL Tier1 Operations Report for 20th January 2016
| Review of Issues during the week 13th to 20th January 2016.
|
- The CMSTape instance has been busy and there have been problems with two, out of five, of its disk servers. (Both disk servers had double disk failures - a possible consequence of the high load on older servers. Both were taken out of service on Monday (11th). One was returned to service the following day - the other remains out.) Some changes were made to the servers in this class to try and improve performance: Applying the change to the Linux I/O scheduled (to 'noop') which it is planned to rollout everywhere, and adjusting one of the Castor parameters. Some throttling in the FTS was also done. The CMS SRM SAM test runs against CMSTape - and this led to a lot of test failures (with error 'user timeout').
- Three files have been declared lost to CMS following problems (double disk failure) on GDSS677.
| Resolved Disk Server Issues
|
- 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.
| 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) 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.
- 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.
| Notable Changes made since the last meeting.
|
- The remaining disk servers in tape backed instances have been upgraded to SL6.
- Roll-out of the change of the Linux I/O scheduler (to 'noop') to all remaining Castor disk servers.
| 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.
|
| Advanced warning for other interventions
|
| The following items are being discussed and are still to be formally scheduled and announced.
|
- Upgrade of remaining Castor disk servers (those in tape-backed service classes) to SL6. This will be transparent to users.
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:
- 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.
|
| 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
|
2016-01-06
|
|
Towards a recommendation on how to configure memory limits for batch jobs
|
| 118722
|
Green
|
Very Urgent
|
In Progress
|
2016-01-08
|
2016-01-11
|
CMS
|
Please check on this file for me
|
| 118549
|
Green
|
Urgent
|
Waiting for Reply
|
2015-12-30
|
2016-01-12
|
CMS
|
Volume Idle about 100% of Volume Requested at T1_UK_RAL
|
| 118494
|
Green
|
Urgent
|
In Progress
|
2015-12-23
|
2015-12-24
|
CMS
|
Xrootd problems???
|
| 118044
|
Yellow
|
Less Urgent
|
Waiting Reply
|
2015-11-30
|
2016-01-05
|
Atlas
|
gLExec hammercloud jobs failing at RAL-LCG2 since October
|
| 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...
|
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
|
| 13/01/16 |
100 |
100 |
100 |
92.0 |
100 |
96 |
100 |
Two SRM test failures on GET (User timeout).
|
| 14/01/16 |
100 |
100 |
100 |
96.0 |
100 |
0 |
100 |
Single SRM test failure on GET (User timeout).
|
| 15/01/16 |
100 |
100 |
100 |
100 |
100 |
0 |
100 |
Atlas Hammercloud tests not run.
|
| 16/01/16 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
| 17/01/16 |
100 |
100 |
100 |
100 |
100 |
75 |
100 |
|
| 18/01/16 |
100 |
100 |
100 |
100 |
100 |
40 |
N/A |
Atlas Hammercloud affected by disk server out of production (test files not available).
|
| 19/01/16 |
100 |
100 |
100 |
100 |
100 |
77 |
100 |
|
