Login or Register to Ask a Question and Join Our Community


AIX

CIO/DIO and JFS2 read ahead

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Operating Systems AIX CIO/DIO and JFS2 read ahead
# 8  
Old 11-14-2008
pstat -a shows, like for example ps aux, only the number of current started aioservers, but not if they are busy or not. With nmon shift+a you see how many are really currently busy and this is on system with an app using AIO, going up and down. Often the maxreqs is forgotten to be configured somewhat large too so the app doesn't get errors regarding to hit the max of queued AIO requests (some "error 5" in Oracle for example).

Nevertheless, we will have to check out if the OP needs AIO at all, which he could and should find out. Maybe he uses it already, no idea. Maybe he offers us some more info to help him.
In our environments I used CIO as a kind of last ressort of tuning, when everything else with AIO and ioo tuning didn't help anymore.
Login or Register to Ask a Question

Previous Thread | Next Thread

8 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Two days ahead

Hi, I have a code that will show one day ahead, how to make it show two days ahead p-dev1-db-tst:/$ day=$(TZ=IST-24 date +%d) p-dev1-db-tst:/$ echo $day 17 p-dev1-db-tst:/$ Regards, Adam (5 Replies)
Discussion started by: answer
5 Replies

2. AIX

AIX JFS2 content

Hello! I have a LPAR with 51GB RAM topas shows 21% of memory for client pages (~11Gb) svmon -G show 2906772 client pages in use (~11Gb) but then i try to investigate per process client memory usage svmon -P -O filtertype=client and summarize inuse column, i get only 347880 pages... (1 Reply)
Discussion started by: sys
1 Replies

3. AIX

Slow NFS when cio/dio enabled

Hi, I have a bit of a NFS problem on AiX 6.1 : When I set the mount to cio and dio - needed for a database app - Everything slows down. The following is copying 700mb, top one is a normal mount bottom one is a mount with the cio/dio option enabled : # ./a.sh Wed Jan 11 11:41:24 GMT 2012... (5 Replies)
Discussion started by: AJCG1976
5 Replies

4. Red Hat

How to enable AIO and DIO on rhel5 64bit?

Hi Friends, Please help me to understand, how to enable async disk IO and Direct disk IO in ext3 filesystem on rhel5. Regards, Arumon (0 Replies)
Discussion started by: arumon
0 Replies

5. AIX

Jfs and jfs2

Hi all, Can anyone define the difference between jfs and jfs2 filesystem as well as usage of jfs log files.... Thanks.... (7 Replies)
Discussion started by: sumathi.k
7 Replies

6. Shell Programming and Scripting

PERL look ahead and behind ...

I would like to search a router config file for "ip address $ip", once found, I want to grab the line just before that contains "interface $interfacetype" basically saying, 10.3.127.9 is assigned to "Loopback1" given the below as an example. interface Loopback1 ip address 10.3.127.9... (1 Reply)
Discussion started by: popeye
1 Replies

7. AIX

JFS and JFS2

hi all, can sumbody give me a link which gives the basic layout of JFS, JFS2 and the veritas file system. and i also want to know about the data structures used in this filsystem thanx in advance (0 Replies)
Discussion started by: anwerreyaz
0 Replies

8. HP-UX

Read-ahead in HP-UX

One cool thing about unix is that it predicts disk blocks that you may need and tries to have them in core before you need them. Over the years, various unix vendors tried various algorithms to improve performance. HP has patented their latest algorithm... Multi-threaded Read Ahead Prediction... (0 Replies)
Discussion started by: Perderabo
0 Replies
Login or Register to Ask a Question

LEARN ABOUT FREEBSD

vm_page_grab

VM_PAGE_GRAB(9) 					   BSD Kernel Developer's Manual					   VM_PAGE_GRAB(9)

NAME

     vm_page_grab -- returns a page from an object

SYNOPSIS

     #include <sys/param.h>
     #include <vm/vm.h>
     #include <vm/vm_page.h>

     vm_page_t
     vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags);

DESCRIPTION

     The vm_page_grab() function returns the page at pindex from the given object.  If the page exists and is busy, vm_page_grab() will sleep
     while waiting for it.  If the page does not exist, it is allocated.  The function sleeps until the allocation request can be satisfied.

     The function requires the object to be locked on entry, and returns with the object locked.  If the vm_page_grab() function sleeps for any
     reason, the object lock is temporary dropped.

     The vm_page_grab() supports all of the flags supported by vm_page_alloc(9).  In addition, vm_page_grab() supports the following flags:

     VM_ALLOC_IGN_SBUSY  When waiting for the busy state of the existing page to drain, only test for exclusive busy; ignore the shared busy
			 counter.

RETURN VALUES

     The vm_page_grab() always returns the page.

SEE ALSO

     vm_page_alloc(9)

AUTHORS

     This manual page was written by Chad David <davidc@acns.ab.ca>.

BSD
								  August 23, 2013							       BSD