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Re: Cache hit percentage
2003-04-10 14:27:25
Are you also using selftunebufpoolsize?
At 02:12 PM 4/10/2003 -0400, you wrote:
Hi all
I've been living with a cache hit percentage at 97-98% for over 2 years
now. I've always wanted to get to 99 but have never been able to. I
finally got my ram doubled
from 1.5 to 3 gb 2 weeks ago. Since then I've been steadily upping the
bufpoolsize with no results whatsoever. Here are the details of the system :
F80 with 4 processors and 3 GB of ram
AIX 5.1
TSM 4.2.3.3
Db sits on 15 gb 10k rpm Hitachi disks in a 7700e (raid5). The database is
alone on the raid group.
2 FC cards for disks connected through Inrange FC9000.
As you can see the database is not mirrored
Volume Name Copy Volume Name Copy Volume
Name Copy Available Allocated Free
(Copy 1) Status (Copy 2) Status (Copy
3) Status Space Space Space
(MB) (MB) (MB)
---------------- ------ ---------------- ------ ----------------
------ --------- --------- --------
/usr/local/tsm/- Sync'd Undef-
Undef- 6,800 6,800 0
bd01/db.bd01 ined ined
/usr/local/tsm/- Sync'd Undef-
Undef- 6,800 6,800 0
bd02/db.bd02 ined ined
/usr/local/tsm/- Sync'd Undef-
Undef- 6,800 6,800 0
bd03/db.bd03 ined ined
/usr/local/tsm/- Sync'd Undef-
Undef- 6,800 6,800 0
bd09/db.bd09 ined ined
/usr/local/tsm/- Sync'd Undef-
Undef- 7,168 1,168 6,000
bd09/db02.bd09 ined ined
My bufpoolsize is now at 921600 (900 mb) and heres the q db f=d :
Available Space (MB): 34,368
Assigned Capacity (MB): 28,368
Maximum Extension (MB): 6,000
Maximum Reduction (MB): 3,512
Page Size (bytes): 4,096
Total Usable Pages: 7,262,208
Used Pages: 5,568,905
Pct Util: 76.7
Max. Pct Util: 78.0
Physical Volumes: 5
Buffer Pool Pages: 230,400
Total Buffer Requests: 298,089,579
Cache Hit Pct.: 97.84
Cache Wait Pct.: 0.00
Backup in Progress?: No
Type of Backup In Progress:
Incrementals Since Last Full: 0
Changed Since Last Backup (MB): 32.38
Percentage Changed: 0.15
Last Complete Backup Date/Time: 04/10/2003 09:00:56
This is at 2:00pm today. I don't really have a performance problem
(atleast I hope not...). Expiration runs between 1 and 2 hours examining
over 4 million files,
deleting between 100,000 and 500,000.
Heres what vmtune says :
vmtune: current values:
-p -P -r -R -f -F -N -W
minperm maxperm minpgahead maxpgahead minfree maxfree pd_npages
maxrandwrt
74189 222569 2 8 120 128 65536 128
-M -w -k -c -b -B -u -l -d
maxpin npswarn npskill numclust numfsbufs hd_pbuf_cnt lvm_bufcnt lrubucket
defps
629137 16384 4096 1 186 640 9 131072 1
-s -n -S -L -g -h
sync_release_ilock nokilluid v_pinshm lgpg_regions lgpg_size
strict_maxperm
0 1 0 0 0 0
-t -j -J -z
maxclient j2_nPagesPer j2_maxRandomWrite j2_nRandomCluster
222569 32 0 0
-Z -q -Q -y
j2_nBufferPer j2_minPageReadAhead j2_maxPageReadAhead memory_affinity
512 2 8 0
-V -i
num_spec_dataseg spec_dataseg_int
0 512
PTA balance threshold percentage = 50.0%
number of valid memory pages = 786421 maxperm=30.0% of real memory
maximum pinable=80.0% of real memory minperm=10.0% of real memory
number of file memory pages = 343322 numperm=46.3% of real memory
number of compressed memory pages = 0 compressed=0.0% of real memory
number of client memory pages = 0 numclient=0.0% of real memory
# of remote pgs sched-pageout = 0 maxclient=30.0% of real memory
I also have a smaller TSM server running on the same machine.The database
is just under 1 gb and the bufpoolsize is at 256000 and I can't get the
cache hit percentage
over 97.
So, are the vmtune settings really that bad? I am not a AIX sysadmin and
haven't quite understood all this vmtune thingy.
Any help or recommendation will be appreciated.
Thanks in advance
Guillaume Gilbert
Storage Administrater
CGI Montreal
Dave Canan
TSM Performance
IBM Advanced Technical Support
ddcanan AT us.ibm DOT com
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