Difference between revisions of "Tier1 Operations Report 2016-01-20"

Latest revision as of 12:54, 20 January 2016

Review of Issues during the week 13th to 20th January 2016.

As reported last week the CMSTape system has been busy - and throughput was compromised by two out of its five disk servers being out of service at the start of last week. An extra disk server was added on Friday (15th Jan). There was also a problem with CMS tests as test files flushed off the disk cache - and took a very long time (some days) to re-recall them from tape.
We note a significant number of disk server problems over recent weeks.

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.

One additional disk server added to CMSTape.
Pilot role accounts and other set-up completed for the support of T2K & NA62 via GridPP Dirac.

Declared in the GOC DB

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.

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...

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
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

@@ Line 59: / Line 59: @@
 | 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;" | Notable Changes made since the last meeting.
 |}
-* The remaining disk servers in tape backed instances have been upgraded to SL6.
+* One additional disk server added to CMSTape.
-* Roll-out of the change of the Linux I/O scheduler (to 'noop') to all remaining Castor disk servers.
+* Pilot role accounts and other set-up completed for the support of T2K & NA62 via GridPP Dirac.
 <!-- *************End Notable Changes made this last week************** ----->
 <!-- ****************************************************************** ----->
@@ Line 102: / Line 102: @@
 |}
 <!-- ******* still to be formally scheduled and/or 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: