[gpfsug-discuss] AFM fun (more!)
Venkateswara R Puvvada
vpuvvada at in.ibm.com
Tue Oct 10 05:56:21 BST 2017
Simon,
>Question 1.
>Can we force the gateway node for the other file-sets to our "02" node.
>I.e. So that we can get the queue services for the other filesets.
AFM automatically maps the fileset to gateway node, and today there is no
option available for users to assign fileset to a particular gateway node.
This feature will be supported in future releases.
>Question 2.
>How can we make AFM actually work for the "facility" file-set. If we shut
>down GPFS on the node, on the secondary node, we'll see log entires like:
>2017-10-09_13:35:30.330+0100: [I] AFM: Found 1069575 local remove
>operations...
>So I'm assuming the massive queue is all file remove operations?
These are the files which were created in cache, and were deleted before
they get replicated to home. AFM recovery will delete them locally. Yes,
it is possible that most of these operations are local remove
operations.Try finding those operations using dump command.
mmfsadm saferdump afm all | grep 'Remove\|Rmdir' | grep local | wc -l
>Alarmingly, we are also seeing entires like:
>2017-10-09_13:54:26.591+0100: [E] AFM: WriteSplit file system rds-cache
>fileset rds-projects-2017 file IDs [5389550.5389550.-1.-1,R] name remote
>error 5
Traces are needed to verify IO errors. Also try disabling the parallel IO
and see if replication speed improves.
mmchfileset device fileset -p afmParallelWriteThreshold=disable
~Venkat (vpuvvada at in.ibm.com)
From: "Simon Thompson (IT Research Support)" <S.J.Thompson at bham.ac.uk>
To: "gpfsug-discuss at spectrumscale.org"
<gpfsug-discuss at spectrumscale.org>
Date: 10/09/2017 06:27 PM
Subject: [gpfsug-discuss] AFM fun (more!)
Sent by: gpfsug-discuss-bounces at spectrumscale.org
Hi All,
We're having fun (ok not fun ...) with AFM.
We have a file-set where the queue length isn't shortening, watching it
over 5 sec periods, the queue length increases by ~600-1000 items, and the
numExec goes up by about 15k.
The queues are steadily rising and we've seen them over 1000000 ...
This is on one particular fileset e.g.:
mmafmctl rds-cache getstate
Mon Oct 9 08:43:58 2017
Fileset Name Fileset Target Cache State
Gateway Node Queue Length Queue numExec
------------ --------------
------------- ------------ ------------ -------------
rds-projects-facility gpfs:///rds/projects/facility Dirty
bber-afmgw01 3068953 520504
rds-projects-2015 gpfs:///rds/projects/2015 Active
bber-afmgw01 0 3
rds-projects-2016 gpfs:///rds/projects/2016 Dirty
bber-afmgw01 1482 70
rds-projects-2017 gpfs:///rds/projects/2017 Dirty
bber-afmgw01 713 9104
bear-apps gpfs:///rds/bear-apps Dirty
bber-afmgw02 3 2472770871
user-homes gpfs:///rds/homes Active
bber-afmgw02 0 19
bear-sysapps gpfs:///rds/bear-sysapps Active
bber-afmgw02 0 4
This is having the effect that other filesets on the same "Gateway" are
not getting their queues processed.
Question 1.
Can we force the gateway node for the other file-sets to our "02" node.
I.e. So that we can get the queue services for the other filesets.
Question 2.
How can we make AFM actually work for the "facility" file-set. If we shut
down GPFS on the node, on the secondary node, we'll see log entires like:
2017-10-09_13:35:30.330+0100: [I] AFM: Found 1069575 local remove
operations...
So I'm assuming the massive queue is all file remove operations?
Alarmingly, we are also seeing entires like:
2017-10-09_13:54:26.591+0100: [E] AFM: WriteSplit file system rds-cache
fileset rds-projects-2017 file IDs [5389550.5389550.-1.-1,R] name remote
error 5
Anyone any suggestions?
Thanks
Simon
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