RAL Tier1 Operations Report for 2nd December 2015
| Review of Issues during the week 25th November to 2nd December 2015.
|
- We ran with a single 10Gbit link between the Tier1 core network and the UKLight router overnight Thursday-Friday 26-27 Nov. The link was saturating. The problem was fixed during the Friday morning with the second 10Gbit link being re-established.
- Three disk servers in AtlasDataDisk crashed during last weekend. This appears to be coincidence - this is our largest disk pool. The types of crash appear similar being in the CPUs. A BIOS update is being applied as this may improve the handling of this type of error. This morning these servers were briefly taken down one after the other for a BIOS update (which may improve the handling of this type of fault).
| Resolved Disk Server Issues
|
- GDSS687 (AtlasDataDisk - D1T0) crashed on Saturday morning (28th Nov). Following initial tests it was returned to service in read-only mode later that day. The type of crash suggests a possible CPU fault.
- GDSS722 (AtlasDataDisk - D1T0) also crashed on Saturday morning (28th Nov). Following initial tests it was returned to service in read-only mode later the following day. Symptoms similar to GDSS687.
- GDSS704 (AtlasDataDisk - D1T0) crashed on Sunday evening (29th Nov). Following initial tests it was returned to service in read-only mode on Monday (30th Nov). Symptoms also similar to GDSS687.
| 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
|
None
| Notable Changes made since the last meeting.
|
- Work to enable the snoplus pilot role for batch.
- Algorithm for the draining of worker nodes to make space for multi-core jobs allowing "pre-emptable" jobs rolled out to one batch of worker nodes.
| Service
|
Scheduled?
|
Outage/At Risk
|
Start
|
End
|
Duration
|
Reason
|
| All Castor (All SRM endpoints)
|
SCHEDULED
|
WARNING
|
09/12/2015 09:30
|
09/12/2015 10:30
|
1 hour
|
Warning on Castor services for short network reconfiguration.
|
| All Castor (All SRM endpoints)
|
SCHEDULED
|
WARNING
|
08/12/2015 09:00
|
08/12/2015 10:00
|
1 hour
|
Warning on Castor services during short network reconfiguration that affects the external data path to/from the Castor storage.
|
| 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.
- Some detailed internal network re-configurations to enable the removal of the old 'core' switch from our network. This includes changing the way the UKLIGHT router connects into the Tier1 network. Following on from this we plan to increase the bandwidth available on the bypass route from 10 to 20Gbit.
- Roll-out of the changed algorithm for the draining of worker nodes to make space for multi-core jobs. The new version allow "pre-emptable" jobs to run in the job slots until they are needed.
Listing by category:
- Databases:
- Switch LFC/3D to new Database Infrastructure.
- Castor:
- Update SRMs to new version (includes updating to SL6).
- Update disk servers to SL6 (ongoing)
- Update to Castor version 2.1.15.
- Networking:
- Complete changes needed to remove the old core switch from the Tier1 network.
- 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.
|
None
| Open GGUS Tickets (Snapshot during morning of meeting)
|
| GGUS ID |
Level |
Urgency |
State |
Creation |
Last Update |
VO |
Subject
|
| 118044
|
Green
|
Less Urgent
|
In Progress
|
2015-11-30
|
2015-11-30
|
Atlas
|
gLExec hammercloud jobs failing at RAL-LCG2 since October
|
| 117846
|
Green
|
Urgent
|
In Progress
|
2015-11-23
|
2015-11-24
|
Atlas
|
ATLAS request- storage consistency checks
|
| 117683
|
Green
|
Less Urgent
|
In Progress
|
2015-11-18
|
2015-11-19
|
|
CASTOR at RAL not publishing GLUE 2
|
| 116866
|
Yellow
|
Less Urgent
|
In Progress
|
2015-10-12
|
2015-11-30
|
SNO+
|
snoplus support at RAL-LCG2 (pilot role)
|
| 116864
|
Amber
|
Urgent
|
In Progress
|
2015-10-12
|
2015-11-20
|
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
|
| 25/11/15 |
100 |
100 |
100 |
100 |
96 |
97 |
100 |
Single SRM test failure “[SRM_INVALID_PATH] No such file or directory”.
|
| 26/11/15 |
100 |
100 |
100 |
96 |
100 |
100 |
100 |
Single SRM test failure on PUT ("Input/output error")
|
| 27/11/15 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
| 28/11/15 |
100 |
100 |
100 |
100 |
96 |
100 |
100 |
Single SRM test failure with "[SRM_INVALID_PATH] No such file or directory"
|
| 29/11/15 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
| 30/11/15 |
100 |
100 |
100 |
95 |
100 |
97 |
N/A |
Looks like SUM monitoring failure.
|
| 01/12/15 |
100 |
100 |
100 |
100 |
100 |
100 |
100 |
|
