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AIX
Lots of page faults and free memory
Post 302380443 by flpgdt on Tuesday 15th of December 2009 07:50:03 AM
12-15-2009
Lots of page faults and free memory
Hello,
I've been reading your forums for quite a while and the great amount of information I find here always come in hand.This time however, I need some specific help...
I have a doubt with an AIX server which I'm failing to understand as I'm new to its concept of memory management...
Straight to the point, I have a sever which yields high number of page faults even though it has plenty of available memory.
This server runs a file-reading-intensive program and an oracle database. I have no serious performance problems so far, but these page faults started to worry me as we plan to stuff some more tasks into this 40GB men server.
I first went on and did my homework reading about AIX VMM (this is my first time with AIX servers
) and got a glance of it's peculiar way of paging everything files and programs and the way it uses a deamon to steal and clean whenever it runs short. Well... I come from Solaris, where short memory causes pages faults. Page faults causes scan-rate and scan-rate most-likely means paging. When I issue my vmstat and see the 'sr' column with 4 digit numbers in a production server, it feels... wrong...
Now, I'll past below my stats.. could someone give me more perspective of what I'm seeing?
System (from nmon startup):
nmon shot (memory and paging):
topas shot:
I appreciate any feedback!
cheers!
f.
I've been reading your forums for quite a while and the great amount of information I find here always come in hand.This time however, I need some specific help...
I have a doubt with an AIX server which I'm failing to understand as I'm new to its concept of memory management...
Straight to the point, I have a sever which yields high number of page faults even though it has plenty of available memory.
This server runs a file-reading-intensive program and an oracle database. I have no serious performance problems so far, but these page faults started to worry me as we plan to stuff some more tasks into this 40GB men server.
I first went on and did my homework reading about AIX VMM (this is my first time with AIX servers
) and got a glance of it's peculiar way of paging everything files and programs and the way it uses a deamon to steal and clean whenever it runs short. Well... I come from Solaris, where short memory causes pages faults. Page faults causes scan-rate and scan-rate most-likely means paging. When I issue my vmstat and see the 'sr' column with 4 digit numbers in a production server, it feels... wrong...Now, I'll past below my stats.. could someone give me more perspective of what I'm seeing?
System (from nmon startup):
Code:
│ 6 - CPUs currently │ │ 6 - CPUs configured │ │ 1900 - MHz CPU clock rate │ │ PowerPC_POWER5 - Processor │ │ 64 bit - Hardware │ │ 64 bit - Kernel │ │ Dynamic - Logical Partition │ │ 5.3.7.1 ML07 - AIX Kernel Version │
Code:
$ vmstat 10 5 r b avm fre re pi po fr sr cy in sy cs us sy id wa pc ec 3 1 6892117 4855669 0 1 0 543 3695 0 3333 26670 12425 82 5 13 0 2.30 91.9 5 0 6892111 4855614 0 0 0 439 3895 0 3245 74660 12366 77 13 10 0 2.37 94.9 3 0 6891110 4856689 0 0 0 635 4806 0 3129 44884 12170 80 6 14 0 2.29 91.4 4 0 6891517 4856185 0 0 0 504 4241 0 3208 41366 13178 80 6 14 0 2.29 91.5 3 0 6891105 4856693 0 0 0 388 2059 0 3162 27696 13502 82 5 12 0 2.33 93.1
Code:
$ vmstat -v
12582896 memory pages
11905361 lruable pages
4858699 free pages
1 memory pools
3055581 pinned pages
80.0 maxpin percentage
10.0 minperm percentage
20.0 maxperm percentage
19.9 numperm percentage
2379986 file pages
0.0 compressed percentage
0 compressed pages
19.9 numclient percentage
20.0 maxclient percentage
2379986 client pages
0 remote pageouts scheduled
5114 pending disk I/Os blocked with no pbuf
151149 paging space I/Os blocked with no psbuf
2484 filesystem I/Os blocked with no fsbuf
41094 client filesystem I/Os blocked with no fsbuf
8101 external pager filesystem I/Os blocked with no fsbuf
0 Virtualized Partition Memory Page Faults
0.00 Time resolving virtualized partition memory page faultsCode:
│ Memory ────────────────────────────────────────────────────────────────────────│ │ Physical PageSpace | pages/sec In Out | FileSystemCache │ │% Used 62.6% 40.5% | to Paging Space 0.0 0.0 | (numperm) 18.7% │ │% Free 37.4% 59.5% | to File System 0.0 207.8 | Process 21.6% │ │MB Used 30779.8MB 7405.8MB | Page Scans 0.0 | System 22.3% │ │MB Free 18372.1MB 10898.2MB | Page Cycles 0.0 | Free 37.4% │ │Total(MB) 49151.9MB 18304.0MB | Page Steals 0.0 | ------ │ │ | Page Faults 5474.0 | Total 100.0% │ │------------------------------------------------------------ | numclient 18.7% │ │Min/Maxperm 4651MB( 9%) 9301MB( 19%) <--% of RAM | maxclient 18.9% │ │Min/Maxfree 960 1088 Total Virtual 65.9GB | User 35.7% │ │Min/Maxpgahead 2 8 Accessed Virtual 27.0GB 41.0% Pinned 24.3% │ │ │ │ Paging-Space ──────────────────────────────────────────────────────────────────│ │ Volume-Group PagingSpace-Name Type LPs MB Used IOpending │ │ rootvg hd6 LV 128 4096 60% 0 Active Auto │ │ rootvg paging00 LV 126 4032 60% 0 Active Auto │ │ rootvg paging01 LV 318 10176 25% 0 Active Auto │ │────────────────────────────────────────────────────────────────────────────────│
Code:
Tue Dec 15 13:45:24 2009 Interval: 2 Cswitch 11920 Readch 3124.7K
Syscall 29015 Writech 2256.6K
Kernel 9.4 |### | Reads 703 Rawin 1
User 82.4 |######################## | Writes 326 Ttyout 238
Wait 0.0 | | Forks 3 Igets 0
Idle 8.2 |### | Execs 3 Namei 2381
Physc = 2.40 %Entc= 96.1 Runqueue 4.5 Dirblk 0
Waitqueue 0.0
Network KBPS I-Pack O-Pack KB-In KB-Out
en4 6243.7 5640.5 1053.0 6179.9 63.7 PAGING MEMORY
lo0 0.0 0.0 0.0 0.0 0.0 Faults 3226 Real,MB 49151
Steals 0 % Comp 42.2
Disk Busy% KBPS TPS KB-Read KB-Writ PgspIn 0 % Noncomp 18.8
hdisk3 2.0 1.7K 28.5 0.0 1.7K PgspOut 0 % Client 18.8
hdisk23 1.5 512.9 4.0 0.0 512.9 PageIn 3
hdisk14 0.5 172.3 35.1 0.0 172.3 PageOut 560 PAGING SPACE
hdisk2 0.0 0.0 0.0 0.0 0.0 Sios 563 Size,MB 18304
% Used 40.0
Name PID CPU% PgSp Owner NFS (calls/sec) % Free 60.0
java 1208454 68.5 144.4 util ServerV2 0
syncd 348408 4.8 0.5 root ClientV2 0 Press:
java 1364098 1.1 60.0 root ServerV3 0 "h" for help
topas 577692 0.0 2.0 util ClientV3 0 "q" to quitcheers!
f.
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