Re: High paging activity with no load

Actually just because the current output of vmstat doesn't show any
paging activity, doesn't mean that the system isn't paging. It just
means that it's not paging right now. Any data that is paged out to
paging space will remain there until it is needed again, which could be
a long time!

I believe that the real problem you are running into is that you
typically need to tune AIX when it is used for a database server,
expecially if the database is filesystem based, since by default, AIX
will use all available memory to cache your database file, even though
they are being cached by the database. Depending on you AIX level,
there are different recommened ways of dealing with this
"double-caching" issue. The "old" way is to tune the "minperm" and
"maxperm" setting to limit the amount of RAM AIX will use for file
caching. The "new" way is you use some mount flags on the database
filesytems to tell AIX not to perform file caching on those
filesystems.

In order to go any further, I would need some further details. What
version of AIX, what database, is the DB filesystem or raw logical
volume based and the output of vmstat -v would help as well.

Hope this helps!

Ashok Sangra wrote:
Hi All,

We have a p570 system with 24 GB RAM and 6 CPUs. It is a database
server and the load is not high at the time the below screenshots are
taken.
Could someone help in figuring out why the paging space used is so much
inspite of no much activity? TIA. -- Ashok

# vmstat 1 10

System configuration: lcpu=12 mem=24576MB

kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------
r b avm fre re pi po fr sr cy in sy cs us sy id wa
0 0 2281919 7862 0 0 0 0 0 0 45 727 481 0 1 98 0
0 0 2281920 7810 0 1 0 0 0 0 129 1915 890 2 1 97 0
0 0 2281920 7610 0 0 0 0 0 0 202 3209 1358 1 2 96 1
0 0 2281920 7608 0 0 0 0 0 0 80 528 572 0 1 99 0
0 0 2281920 7608 0 0 0 0 0 0 74 1415 493 2 1 97 0
0 0 2282321 7206 0 0 0 0 0 0 220 2079 719 1 1 97 1
0 0 2282321 7199 0 0 0 0 0 0 57 1169 474 0 1 99 0
1 0 2282353 7157 0 0 0 0 0 0 116 1076 544 1 1 98 0
0 0 2282565 6945 0 0 0 0 0 0 65 1749 505 1 1 98 0
0 0 2282563 6940 0 0 0 0 0 0 111 3246 910 1 1 98 0
# lsps -a
Page Space Physical Volume Volume Group Size %Used Active
Auto Type
paging00 hdisk25 pagingvg 4096MB 25 yes
yes lv
hd6 hdisk0 rootvg 2048MB 50 yes
yes lv

.

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