Hi Kevin,

IMHO, safe to just run it again.

You can also run it with '-I test -L 6' again and look through the output. But I don't think you can "break" anything by having it scan and/or move data.

Can you post the full command line that you use to run it?

The behavior you describe is odd; you say it prints out the "files migrated successfully" message, but the files didn't actually get migrated? Turn up the debug param and have it print every file as it is moving it or something.

Regards,
Alex

On 4/17/17 8:24 AM, Buterbaugh, Kevin L wrote:
Hi Marc,

I do understand what you’re saying about mmapplypolicy deciding it only
needed to move ~1.8 million files to fill the capacity pool to ~98%
full.  However, it is now more than 24 hours since the mmapplypolicy
finished “successfully” and:

Disks in storage pool: gpfs23capacity (Maximum disk size allowed is 519 TB)
eon35Ansd               58.2T       35 No       Yes          29.66T (
51%)        64.16G ( 0%)
eon35Dnsd               58.2T       35 No       Yes          29.66T (
51%)        64.61G ( 0%)
                -------------
-------------------- -------------------
(pool total)           116.4T                                59.33T (
51%)        128.8G ( 0%)

And yes, I did run the mmapplypolicy with “-I yes” … here’s the
partially redacted command line:

/usr/lpp/mmfs/bin/mmapplypolicy gpfs23 -A 75 -a 4 -g <some folder on
another gpfs filesystem> -I yes -L 1 -P ~/gpfs/gpfs23_migration.policy
-N some,list,of,NSD,server,nodes

And here’s that policy file:

define(access_age,(DAYS(CURRENT_TIMESTAMP) - DAYS(ACCESS_TIME)))
define(GB_ALLOCATED,(KB_ALLOCATED/1048576.0))

RULE 'OldStuff'
  MIGRATE FROM POOL 'gpfs23data'
  TO POOL 'gpfs23capacity'
  LIMIT(98)
  WHERE ((access_age > 14) AND (KB_ALLOCATED > 3584))

RULE 'INeedThatAfterAll'
  MIGRATE FROM POOL 'gpfs23capacity'
  TO POOL 'gpfs23data'
  LIMIT(75)
  WHERE (access_age < 14)

The one thing that has changed is that formerly I only ran the migration
in one direction at a time … i.e. I used to have those two rules in two
separate files and would run an mmapplypolicy using the OldStuff rule
the 1st weekend of the month and run the other rule the other weekends
of the month.  This is the 1st weekend that I attempted to run an
mmapplypolicy that did both at the same time.  Did I mess something up
with that?

I have not run it again yet because we also run migrations on the other
filesystem that we are still in the process of migrating off of.  So
gpfs23 goes 1st and as soon as it’s done the other filesystem migration
kicks off.  I don’t like to run two migrations simultaneously if at all
possible.  The 2nd migration ran until this morning, when it was
unfortunately terminated by a network switch crash that has also had me
tied up all morning until now.  :-(

And yes, there is something else going on … well, was going on - the
network switch crash killed this too … I have been running an rsync on
one particular ~80TB directory tree from the old filesystem to gpfs23.
 I understand that the migration wouldn’t know about those files and
that’s fine … I just don’t understand why mmapplypolicy said it was
going to fill the capacity pool to 98% but didn’t do it … wait,
mmapplypolicy hasn’t gone into politics, has it?!?  ;-)

Thanks - and again, if I should open a PMR for this please let me know...

Kevin

On Apr 16, 2017, at 2:15 PM, Marc A Kaplan <[email protected]
<mailto:[email protected]>> wrote:

Let's look at how mmapplypolicy does the reckoning.
Before it starts, it see your pools as:

[I] GPFS Current Data Pool Utilization in KB and %
Pool_Name                   KB_Occupied        KB_Total  Percent_Occupied
gpfs23capacity              55365193728    124983549952     44.297984614%
gpfs23data                 166747037696    343753326592     48.507759721%
system                                0               0
 0.000000000% (no user data)
[I] 75142046 of 209715200 inodes used: 35.830520%.

Your rule says you want to migrate data to gpfs23capacity, up to 98% full:

RULE 'OldStuff'
  MIGRATE FROM POOL 'gpfs23data'
  TO POOL 'gpfs23capacity'
  LIMIT(98) WHERE ...

We scan your files and find and reckon...
[I] Summary of Rule Applicability and File Choices:
 Rule#      Hit_Cnt          KB_Hit          Chosen       KB_Chosen
       KB_Ill     Rule
     0      5255960     237675081344        1868858     67355430720
            0     RULE 'OldStuff' MIGRATE FROM POOL 'gpfs23data' TO
POOL 'gpfs23capacity' LIMIT(98.000000) WHERE(.)

So yes, 5.25Million files match the rule, but the utility chooses
1.868Million files that add up to 67,355GB and figures that if it
migrates those to gpfs23capacity,
(and also figuring the other migrations  by your second rule)then
gpfs23 will end up  97.9999% full.
We show you that with our "predictions" message.

Predicted Data Pool Utilization in KB and %:
Pool_Name                   KB_Occupied        KB_Total  Percent_Occupied
gpfs23capacity             122483878944    124983549952     97.999999993%
gpfs23data                 104742360032    343753326592     30.470209865%

So that's why it chooses to migrate "only" 67GB....

See? Makes sense to me.

Questions:
Did you run with -I yes or -I defer ?

Were some of the files illreplicated or illplaced?

Did you give the cluster-wide space reckoning protocols time to see
the changes?  mmdf is usually "behind" by some non-neglible amount of
time.

What else is going on?
If  you're moving  or deleting or creating data by other means while
mmapplypolicy is running -- it doesn't "know" about that!

Run it again!

<ATT00001.gif>



From:        "Buterbaugh, Kevin L" <[email protected]
<mailto:[email protected]>>
To:        gpfsug main discussion list
<[email protected]
<mailto:[email protected]>>
Date:        04/16/2017 09:47 AM
Subject:        [gpfsug-discuss] mmapplypolicy didn't migrate
everything it should        have - why not?
Sent by:        [email protected]
<mailto:[email protected]>
------------------------------------------------------------------------



Hi All,

First off, I can open a PMR for this if I need to.  Second, I am far
from an mmapplypolicy guru.  With that out of the way … I have an
mmapplypolicy job that didn’t migrate anywhere close to what it could
/ should have.  From the log file I have it create, here is the part
where it shows the policies I told it to invoke:

[I] Qos 'maintenance' configured as inf
[I] GPFS Current Data Pool Utilization in KB and %
Pool_Name                   KB_Occupied        KB_Total  Percent_Occupied
gpfs23capacity              55365193728    124983549952     44.297984614%
gpfs23data                 166747037696    343753326592     48.507759721%
system                                0               0
 0.000000000% (no user data)
[I] 75142046 of 209715200 inodes used: 35.830520%.
[I] Loaded policy rules from /root/gpfs/gpfs23_migration.policy.
Evaluating policy rules with CURRENT_TIMESTAMP = 2017-04-15@01:13:02 UTC
Parsed 2 policy rules.

RULE 'OldStuff'
  MIGRATE FROM POOL 'gpfs23data'
  TO POOL 'gpfs23capacity'
  LIMIT(98)
  WHERE (((DAYS(CURRENT_TIMESTAMP) - DAYS(ACCESS_TIME)) > 14) AND
(KB_ALLOCATED > 3584))

RULE 'INeedThatAfterAll'
  MIGRATE FROM POOL 'gpfs23capacity'
  TO POOL 'gpfs23data'
  LIMIT(75)
  WHERE ((DAYS(CURRENT_TIMESTAMP) - DAYS(ACCESS_TIME)) < 14)

And then the log shows it scanning all the directories and then says,
"OK, here’s what I’m going to do":

[I] Summary of Rule Applicability and File Choices:
 Rule#      Hit_Cnt          KB_Hit          Chosen       KB_Chosen
       KB_Ill     Rule
     0      5255960     237675081344        1868858     67355430720
            0     RULE 'OldStuff' MIGRATE FROM POOL 'gpfs23data' TO
POOL 'gpfs23capacity' LIMIT(98.000000) WHERE(.)
     1          611       236745504             611       236745504
            0     RULE 'INeedThatAfterAll' MIGRATE FROM POOL
'gpfs23capacity' TO POOL 'gpfs23data' LIMIT(75.000000) WHERE(.)

[I] Filesystem objects with no applicable rules: 414911602.

[I] GPFS Policy Decisions and File Choice Totals:
 Chose to migrate 67592176224KB: 1869469 of 5256571 candidates;
Predicted Data Pool Utilization in KB and %:
Pool_Name                   KB_Occupied        KB_Total  Percent_Occupied
gpfs23capacity             122483878944    124983549952     97.999999993%
gpfs23data                 104742360032    343753326592     30.470209865%
system                                0               0
 0.000000000% (no user data)

Notice that it says it’s only going to migrate less than 2 million of
the 5.25 million candidate files!!  And sure enough, that’s all it did:

[I] A total of 1869469 files have been migrated, deleted or processed
by an EXTERNAL EXEC/script;
        0 'skipped' files and/or errors.

And, not surprisingly, the gpfs23capacity pool on gpfs23 is nowhere
near 98% full:

Disks in storage pool: gpfs23capacity (Maximum disk size allowed is
519 TB)
eon35Ansd               58.2T       35 No       Yes          29.54T (
51%)        63.93G ( 0%)
eon35Dnsd               58.2T       35 No       Yes          29.54T (
51%)        64.39G ( 0%)
                -------------
-------------------- -------------------
(pool total)           116.4T                                59.08T (
51%)        128.3G ( 0%)

I don’t understand why it only migrated a small subset of what it
could / should have?

We are doing a migration from one filesystem (gpfs21) to gpfs23 and I
really need to stuff my gpfs23capacity pool as full of data as I can
to keep the migration going.  Any ideas anyone?  Thanks in advance…

—
Kevin Buterbaugh - Senior System Administrator
Vanderbilt University - Advanced Computing Center for Research and
Education
[email protected]_
<mailto:[email protected]>- (615)875-9633


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