RAL Tier1 Operations Report for 6th January 2016
| Review of Issues during the fortnight 23rd December 2015 to 6th January 2016.
|
- There were significant batch problems during the first part of this fortnight. Problems had been progressively getting worse. These problems were resolved between Christmas and the New Year. The problems were found to be partly excessive load on the Condor components running on the ARC CEs. This load coming from the new draining algorithm. There was an additional problem caused by a parameter change introduced with a Condor update. This problem was initially reported at the last meeting as a high rate of batch job failures seen by LHCb since around the 9th December.
- Over the holiday period we were running with 2*10Gbit link for the "bypass" route that is used by data traffic that does not use the OPN. However, it was found that the ACLs that act as a firewall over this route were not in place. There have been problems this week as we have attempted to put the ACLs back in place and still run with the 2*10Gbit link. There were significant problems during last night (5-6 Jan). We have now reverted to a single 10Gbit link for this connection.
- Over the new year (31/12-01/01) AtlasDataDisk filled up. This caused the Atlas SAM tests to fail. There was very high load on the couple of servers that did have some remaining space - which in turn led to read failures as well. The problem s was alleviated when Atlas changed their deletion algorith on the 2nd Jan to preferentially delete larger files first and free space became available.
- There was a problem with all Castor instances during the day on Monday 4th January when there were internal problems within Castor. The problem lasted roughly the length of the working day but is not yet understood.
| Resolved Disk Server Issues
|
- GDSS665 (AtlasTape) failed on the 21st Dec. It was rebooted and all canbemigr files migrated to tape. A faulty disk drive was replaced. System returned to production on Christmas Day!
- GDSS620 (GenTape - D0T1) failed on the 22nd Dec. It was rebooted and all canbemigr files migrated to tape. Following testing it was put back into service on the 24th December. (But note that it has since failed yet again).
- GDSS656 (lhcbRawRdst - D0T1) has a double disk failure on the 23 Dec. It was removed from service while the disks were replaced and the RAID array rebuilt. It was returned to service on the 24th December.
- GDSS675 (CMSTape - D0T1) failed on the afternoon of 23rd December. A faulty drive was found. Also returned to production on Christmas day.
- GDSS770 (AtlasDataDisk - D1T0) crashed on the 31st December. Following checks it was returned to service later that day.
- GDSS710 (CMSDisk - D1T0) Failed on the 2nd January. Following checks it was returned to service the following day.
- GDSS648 (LHCb -User - D1T0) was taken out of service on the 4th January as two disks had failed. Returned to production the following day.
- GDSS707 (AtlasDataDisk - D1T0) Was taken out of service on the 4th January - one of the Castor processes was failing to run. Following investigations it was returned to production in read-only mode the next 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. 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.
- GDSS677 (CMSTape - D0T1) failed yesterday evening (5th Jan). It is being worked on.
| Notable Changes made since the last meeting.
|
- Following problems the 'bypass' network link has been dropped back to a single 10Gbit link.
- The new batch draining script has been modified to eliminate load on Condor.
- The quarterly UPS/Generator load test took place successfully this morning.
- A power supply was replaced on Monday 4th Jan. in the disk array that hosts the Castor standby databases. This had reported problems over the holiday period.
None
| 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 disk servers in tape-backed service classes 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.
|
| Service
|
Scheduled?
|
Outage/At Risk
|
Start
|
End
|
Duration
|
Reason
|
| srm-atlas.gridpp.rl.ac.uk,
|
UNSCHEDULED
|
WARNING
|
01/01/2016 04:30
|
01/01/2016 12:27
|
7 hours and 57 minutes
|
one of four machines in DNS alias down, so some transfer failures possible
|
| Open GGUS Tickets (Snapshot during morning of meeting)
|
| GGUS ID |
Level |
Urgency |
State |
Creation |
Last Update |
VO |
Subject
|
| 118631
|
Green
|
Very Urgent
|
Waiting Reply
|
2016-01-05
|
2016-01-06
|
Atlas
|
RAL-LCG2 'unable-to-connect' destination transfer errors
|
| 118573
|
Green
|
Urgent
|
In Progress
|
2016-01-02
|
2016-01-05
|
Atlas
|
A lot of RAL-LCG2 data transfers fails
|
| 118549
|
Green
|
Urgent
|
Waiting for Reply
|
2015-12-30
|
2016-01-05
|
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???
|
| 118209
|
Green
|
Less Urgent
|
In Progress
|
2015-12-15
|
2015-12-18
|
|
Enabling CVMFS for the vo.neugrid.eu VO
|
| 118044
|
Green
|
Less Urgent
|
Waiting Reply
|
2015-11-30
|
2016-01-05
|
Atlas
|
gLExec hammercloud jobs failing at RAL-LCG2 since October
|
| 117846
|
Green
|
Urgent
|
Waiting for Reply
|
2015-11-23
|
2015-12-22
|
Atlas
|
ATLAS request- storage consistency checks
|
| 117683
|
Green
|
Less Urgent
|
In Progress
|
2015-11-18
|
2016-01-05
|
|
CASTOR at RAL not publishing GLUE 2
|
| 116866
|
Amber
|
Less Urgent
|
On Hold
|
2015-10-12
|
2015-12-18
|
SNO+
|
snoplus support at RAL-LCG2 (pilot role)
|
| 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
|
| 23/12/15 |
100 |
100 |
100 |
96 |
100 |
100 |
100 |
Single SRM test failure. Could not find the test file.
|
| 24/12/15 |
100 |
100 |
97 |
100 |
100 |
100 |
100 |
SRM failure: File deletion failed in token. Error message: __main__.TimeoutException
|
| 25/12/15 |
100 |
100 |
100 |
100 |
100 |
96 |
100 |
|
| 26/12/15 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
| 27/12/15 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
| 28/12/15 |
100 |
100 |
100 |
100 |
100 |
86 |
100 |
|
| 29/12/15 |
100 |
100 |
100 |
100 |
100 |
0 |
100 |
|
| 30/12/15 |
100 |
100 |
100 |
100 |
100 |
0 |
100 |
|
| 31/12/15 |
100 |
100 |
92 |
96 |
100 |
100 |
100 |
CMS: Single SRM failure. Atlas: AtlasDataDisk full
|
| 01/01/16 |
100 |
100 |
6 |
100 |
100 |
55 |
100 |
AtlasDataDisk full
|
| 02/01/16 |
100 |
100 |
40 |
100 |
100 |
94 |
100 |
AtlasDataDisk full
|
| 03/01/16 |
100 |
100 |
100 |
100 |
100 |
97 |
N/A |
|
| 04/01/16 |
96.1 |
100 |
80 |
85 |
85 |
100 |
100 |
Internal communication problem (or something) affected Castor.
|
| 05/01/16 |
99.6 |
100 |
68 |
68 |
68 |
91 |
N/A |
Problem on the Bypass (non-OPN) link.
|
