Difference between revisions of "Tier1 Operations Report 2015-12-02"

Revision as of 10:12, 2 December 2015

Review of Issues during the week 25th November to 2nd December 2015.

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. This morning this server was briefly taken down for a BIOS update (which may improve the handling of this type of 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.

Declared in the GOC DB

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. As part of this we plan to increase the bandwidth available on the bypass route from 10 to 20Gbit.
Implementing a 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...

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
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

@@ Line 33: / Line 33: @@
 | 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;" | 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.
+* 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.
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