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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Excessive Paging - AIX Related?
Mount the file system that holds your temporary tablespace in Direct mode
(non-buffered mode) and try to find if AIX has something similar to the
priority paging in Solaris.
Also Raw partitions are good at least (in your case) for temporary tablespace.
Also check if your tablespace is defined as temporary.
Regards,
Waleed
-----Original Message-----
Sent: Thursday, December 20, 2001 6:10 PM
To: Multiple recipients of list ORACLE-L
I am resolved that the trouble is not enough swap and not enough aio processes. I think this will significantly improve the system. Spreading swap will be my next push if I still have trouble. vmtune will be last which is basically what I wanted to confirm.
AIX vmstat shows
kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------r b avm fre re pi po fr sr cy in sy cs us sy id wa 0 0 522715 4737 0 1 1 39 115 0 147 440 151 3 1 92 3 0 2 522715 4646 0 0 0 0 0 0 522 1169 133 3 4 91 2 0 2 522715 4646 0 0 0 0 0 0 472 564 60 0 0 99 0
However topas shows more info about where the pageing is occuring i.e. good/normal paging as oposed to bad paging as seen below. PgspIn and PgspOut are the bad kind.
Topas Monitor for host: FOO EVENTS/QUEUES FILE/TTY
Thu Dec 20 18:10:02 2001 Interval: 2 Cswitch 2625 Readch
11505467
Syscall 40623 Writech
883896
Kernel 42.7 |############ | Reads 5506 Rawin
0
User 13.1 |#### | Writes 514 Ttyout
318
Wait 9.3 |### | Forks 179 Igets
9
Idle 34.7 |########## | Execs 177 Namei
6369
Runqueue 7.5 Dirblk
49
en1 9.4 25.9 16.9 3.1 6.3
en0 1.4 10.9 3.9 0.9 0.5 PAGING MEMORY
Faults 30366 Real,MB
4095
Disk Busy% KBPS TPS KB-Read KB-Writ Steals 0 % Comp
39.2
hdisk0 47.4 574.7 92.3 9.9 564.8 PgspIn 2 % Noncomp
61.4
hdisk1 41.9 572.8 89.8 0.0 572.8 PgspOut 0 % Client
348
hdisk3 1.4 337.3 10.4 0.0 337.3 PageIn 66 2
0992
hdisk10 0.0 0.0 0.0 0.0 0.0 PageOut 229 PAGING
SPACE
hdisk4 0.0 3.9 0.4 0.0 3.9 Sios 118 Size,MB
2992
% Used
22.3
dm_ep_eng(11094) 12.5% PgSp: 1.0mb root % Free
77.6
init (1) 6.0% PgSp: 0.6mb root
ksh (35124) 5.0% PgSp: 0.3mb oracle
ksh (15854) 4.00 10.0.4mb oracle 4 Press "h" for help
screen.
ksh (68298) 4.05 PgSp: 0.3mb oracle 5 Press "q" to quit
program.
sadc (59690) 3.0% PgSp: 0.1mb root
ksh (53722) 3.0% PgSp: 0.3mb oracle
ksh (63038) 2.0% PgSp: 0.3mb oracle
ksh (27478) 2.0% PgSp: 0.3mb oracle
ksh (61336) 2.0% PgSp: 0.3mb oracle
-----Original Message-----
Sent: Thursday, December 20, 2001 3:40 PM
To: Multiple recipients of list ORACLE-L
Ethan,
AIX performs all file i/o via the OS's virtual memory. In other words, the
VM (which is a combination of both the RAM and the Swap) is used for both
executable (OS/user code) and user's memory area as well as for I/O buffers.
This allocation is dynamic and certain upper and lower limits are set by the
parameters in vmtune. At times of high i/o, you will find that the 'fre' mem
(seen in vmstat' goes down drastically and the po/fr/sr goes up drastically
as a result of old memory pages that served file i/o buffers are paged out.
This is normal and in line with what you are observing and is similar to
Solaris.
What you *should* be concerned about is excessive values in 'pi' as this indicates excessive paging-*in*, probably due to earlier pageouts of live pages that are still required. You are probably seeing high I/o waits since there is a lot of writes (paging out) to the swap area. 'iostat' will probably indicate that disks that host your swap area are almost 100% loaded. In this case, you should make sure that you (a) spread out swap on multiple disks, making sure that they are NOT on RAID-5. (b) allocate dedicated drives to swap areas if possible (no RAID5!).
FWIW, vmstat in Solaris is able to distinguish between pi/po values for executable, file i/o and 'other' (?) types of paging. Can you find out for us if AIX also provides this? (Don't have access to an AIX box).
Merry Christmas and a Blessed New Year!
John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Post, Ethan INET: Ethan.Post_at_ps.net Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-LReceived on Fri Dec 21 2001 - 11:35:29 CST
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also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Khedr, Waleed INET: Waleed.Khedr_at_FMR.COM Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L
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