Cached reads going to 0.00%

I've noticed this a couple of times in onstat, for no apparent reason cached reads go from 95% or so to 0.00% and then slowly build back up to 95% over the next 24hours or so. There's a cronjob that runs at 8, noon, 5 and midnight that records a few interesting statistics on the machine. We're running Informix 7.31.UD6 upgrading to a 9.4 on HPUX 11i. The hardware is a little old and we have had problems with disk failures in the recent past, any clues? Chris S. Noon stats run: Uptime 12:05pm up 18 days, 5 mins, 57 users, load average: 0.46, 0.41, 0.41 Free Disk Space Filesystem kbytes used avail %used Mounted on /dev/vg00/lvol3 143360 88747 51249 63% / /dev/vg00/lvol1 159509 40391 103167 28% /stand /dev/vg00/lvol8 2048000 1541798 477349 76% /var /dev/vg00/lvol7 2048000 1894310 144902 93% /usr /dev/vg00/lvol4 524288 127645 377515 25% /tmp /dev/vg00/lvol6 2457600 1888515 533739 78% /opt /dev/vg00/lvol12 155648 1141 144858 1% /opt/perl5 /dev/vg00/lvol19 1024000 889055 126530 88% /opt/informix /dev/vg00/lvol11 307200 10529 278156 4% /opt/gnu /dev/vg00/lvol10 1024000 379940 603844 39% /opt/carstrain /dev/vg00/lvol9 3072000 1589200 1390347 53% /opt/carsi /dev/vg00/lvol20 3072000 1229736 1729229 42% /opt/carsi/smo /dev/vg00/lvol13 2048000 334130 1606763 17% /opt/apache /dev/vg00/lvol5 20480 1114 18161 6% /home /dev/vg00/lvol14 2457600 1594848 810532 66% /home/carsids Database Free Space Name KB Size KB Free KB Used Percent ------------ ------- ------- ------- ------- root 1024000 668062 355938 34.8% dbs0 12288000 4632328 7655672 62.3% temp1 512000 511434 566 0.1% temp0 512000 511498 502 0.1% ------------ ------- ------- ------- ------- Total 14336000 6323322 8012678 Logical Logs 300000 243820 56180 18.7% who prices pts/tb Jun 15 17:54 stuberj pts/tc Jun 16 07:05 berryj pts/td Jun 16 07:33 watkinst pts/te Jun 16 07:37 skaggsk pts/tf Jun 16 07:39 engelkek pts/tg Jun 16 07:39 bishopa pts/th Jun 16 07:40 dennisg pts/ti Jun 15 11:52 hammerm pts/tj Jun 16 08:04 moughond pts/tl Jun 16 07:41 rueggt pts/tm Jun 15 08:13 westbros pts/tn Jun 16 07:41 hoffpowj pts/tp Jun 16 07:45 hellmutk pts/tq Jun 16 07:54 clarka pts/tr Jun 16 08:09 hammd pts/ts Jun 15 08:29 maloned pts/tt Jun 15 08:53 barnesc pts/tu Jun 16 07:56 wessonc pts/tw Jun 16 07:59 daviss pts/tx Jun 16 08:12 deyoungj pts/ty Jun 16 08:08 jonesa pts/tz Jun 16 08:14 sarverl pts/tA Jun 16 08:09 murleyt pts/tB Jun 16 08:09 mcgheeb pts/tC Jun 16 09:06 hammerm pts/tD Jun 16 08:16 hoodm pts/tE Jun 16 08:19 ackerk pts/tF Jun 16 09:24 keilersv pts/tG Jun 16 08:21 legera pts/tH Jun 16 08:36 hellmutk pts/tI Jun 16 08:23 moughond pts/tJ Jun 16 08:24 smithc pts/tL Jun 16 08:35 weatherb pts/tM Jun 16 10:00 bullardk pts/tN Jun 16 08:44 westbros pts/tO Jun 16 08:42 ardend pts/tP Jun 16 11:16 tilleryl pts/tQ Jun 16 09:13 childree pts/tR Jun 16 08:47 mccalluj pts/tS Jun 15 10:17 dickersd pts/tT Jun 15 10:21 westbros pts/tU Jun 16 12:01 royek pts/tV Jun 16 09:22 edwardje pts/tW Jun 16 10:26 dickersd pts/tX Jun 15 10:25 burrowsr pts/tY Jun 16 09:44 harperk pts/tZ Jun 16 09:28 reedd pts/t2 Jun 16 11:28 bradfork pts/t3 Jun 16 10:01 bakerl pts/t4 Jun 16 10:52 rueggt pts/t5 Jun 15 11:30 waltonj pts/t7 Jun 16 11:40 holleyj pts/t8 Jun 16 10:46 prices pts/t9 Jun 16 10:44 holleyj pts/tab Jun 16 11:31 erpeldic pts/tbb Jun 16 11:32 powellc pts/tdb Jun 16 11:47 Database Status Informix Dynamic Server Version 7.31.UD6 -- On-Line -- Up 18 days 00:03:58 -- 415112 Kbytes Userthreads address flags sessid user tty wait tout locks nreads nwrites d11cc018 ---P--D 1 root - 0 0 0 3496 24626 d11cc520 ---P--F 0 root - 0 0 0 0 508061 d11cca28 ---P--F 0 root - 0 0 0 0 386810 d11ccf30 ---P--F 0 root - 0 0 0 0 354661 d11cd438 ---P--F 0 root - 0 0 0 0 337935 d11cd940 ---P--F 0 root - 0 0 0 0 388000 d11cde48 ---P--F 0 root - 0 0 0 0 388613 d11ce350 ---P--F 0 root - 0 0 0 0 281473 d11ce858 ---P--F 0 root - 0 0 0 0 161051 d11ced60 ---P--- 14 root - 0 0 0 0 816 d11cf268 ---P--B 15 root - 0 0 0 1941 3472 d11cf770 Y--P--- 255079 carsu tg d68d3fb8 0 1 555 0 d11cfc78 Y--P--- 253225 prices tb d40d6c78 0 1 20 0 d11d0180 ---P--D 21 root - 0 0 0 0 0 <SNIP> d5be60e0 Y--P--- 256093 ackerk tF d488eac0 0 1 0 0 278 active, 384 total, 380 maximum concurrent Profile dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached 61252555 63656511 38272855 0.00 4388404 8766681 84453462 94.80 isamtot open start read write rewrite delete commit rollbk 3701808677 65244515 301778893 2584721159 65058168 1805574 587069 560468 1814 gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs 0 0 0 0 0 0 0 ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes 1065 0 0 325269.04 13615.07 1298 3452 bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans 9670592 339 420679365 0 0 183 114309 8420667 ixda-RA idx-RA da-RA RA-pgsused lchwaits 15789770 1108760 29257518 46141844 30166786 Database Locks --------- LISTLOCK: Lock Listing for cars database --------- Table Level Type User Ses ID ---------------------- ------------- ------------------------ ---------- ------ cars.prog_enr_rec row:0x13f005 SR carsu 246346 cars.prog_enr_rec table intent-shared carsu 246346 cars.stufa_rec row:0xe4d01 update carsu 255076 cars.stufa_rec table intent-exclusive carsu 257326 cars.stufa_rec table intent-exclusive carsu 255062 cars.stufa_rec row:0x106f05 update carsu 255078 cars.stufa_rec row:0x120103 update carsu 254986 cars.stufa_rec table intent-exclusive carsu 254986 cars.stufa_rec row:0x116d03 update carsu 260351 cars.stufa_rec table intent-exclusive carsu 255076 cars.stufa_rec table intent-exclusive carsu 255144 cars.stufa_rec table intent-exclusive carsu 260351 cars.stufa_rec table intent-exclusive carsu 255078 cars.stufa_rec row:0x111f01 update carsu 257326 cars.stufa_rec row:0xfe801 update carsu 255144 cars.stufa_rec row:0x12ee07 update carsu 255062 cars.sysdistrib page:0xc5400 intent-shared carsu 255062 cars.sysdistrib page:0xc5400 intent-shared carsu 255076 cars.sysdistrib page:0x1300 intent-shared ackerk 258640 cars.sysdistrib table intent-shared carsu 255078 cars.sysdistrib table intent-shared keilersv 257987 cars.sysdistrib page:0xc5400 intent-shared keilersv 257987 cars.sysdistrib page:0x1300 intent-shared carsu 255144 cars.sysdistrib table intent-shared burrowsr 258393 cars.sysdistrib table intent-shared edwardje 259145 cars.sysdistrib table intent-shared ackerk 258640 cars.sysdistrib page:0xc5400 intent-shared edwardje 258099 cars.sysdistrib table intent-shared carsu 255062 cars.sysdistrib page:0x1300 intent-shared carsu 255076 cars.sysdistrib table intent-shared edwardje 258099 cars.sysdistrib table intent-shared carsu 260351 cars.sysdistrib page:0x1300 intent-shared burrowsr 258393 cars.sysdistrib table intent-shared carsu 257326 cars.sysdistrib page:0xc5400 intent-shared moughond 255082 cars.sysdistrib table intent-shared burrowsr 256779 cars.sysdistrib table intent-shared carsu 255076 cars.sysdistrib pag

CHRIS SALCH wrote: > I've noticed this a couple of times in onstat, for no apparent reason cached > reads go from 95% or so to 0.00% and then slowly build back up to 95% over the > next 24hours or so. There's a cronjob that runs at 8, noon, 5 and midnight > that records a few interesting statistics on the machine. We're running > Informix 7.31.UD6 upgrading to a 9.4 on HPUX 11i. The hardware is a little old > and we have had problems with disk failures in the recent past, any clues? > > Chris S. > > The numbers for dskreads, pagreads, bufreads, ... are stored in 32bit values. So there is a max value of 2^31. After reaching the maximum the counter starts with zero again which leads to this percentages values. You may use "onstat -z" at the end of your jobs to reset all counters to zero. So you get the stats values for the interval between two jobs.

Yes, we have the same on IDS7.31 seems to be normal, overrun of some internal profile counters. So you have to reset the counters once week or so : onstat -z Yves -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] Sent: 18 June 2006 05:55 To: ids@iiug.org Subject: Cached reads going to 0.00% [6973] I've noticed this a couple of times in onstat, for no apparent reason cached reads go from 95% or so to 0.00% and then slowly build back up to 95% over the next 24hours or so. There's a cronjob that runs at 8, noon, 5 and midnight that records a few interesting statistics on the machine. We're running Informix 7.31.UD6 upgrading to a 9.4 on HPUX 11i. The hardware is a little old and we have had problems with disk failures in the recent past, any clues? Chris S. Noon stats run: Uptime 12:05pm up 18 days, 5 mins, 57 users, load average: 0.46, 0.41, 0.41 Free Disk Space Filesystem kbytes used avail %used Mounted on /dev/vg00/lvol3 143360 88747 51249 63% / /dev/vg00/lvol1 159509 40391 103167 28% /stand /dev/vg00/lvol8 2048000 1541798 477349 76% /var /dev/vg00/lvol7 2048000 1894310 144902 93% /usr /dev/vg00/lvol4 524288 127645 377515 25% /tmp /dev/vg00/lvol6 2457600 1888515 533739 78% /opt /dev/vg00/lvol12 155648 1141 144858 1% /opt/perl5 /dev/vg00/lvol19 1024000 889055 126530 88% /opt/informix /dev/vg00/lvol11 307200 10529 278156 4% /opt/gnu /dev/vg00/lvol10 1024000 379940 603844 39% /opt/carstrain /dev/vg00/lvol9 3072000 1589200 1390347 53% /opt/carsi /dev/vg00/lvol20 3072000 1229736 1729229 42% /opt/carsi/smo /dev/vg00/lvol13 2048000 334130 1606763 17% /opt/apache /dev/vg00/lvol5 20480 1114 18161 6% /home /dev/vg00/lvol14 2457600 1594848 810532 66% /home/carsids Database Free Space Name KB Size KB Free KB Used Percent ------------ ------- ------- ------- ------- root 1024000 668062 355938 34.8% dbs0 12288000 4632328 7655672 62.3% temp1 512000 511434 566 0.1% temp0 512000 511498 502 0.1% ------------ ------- ------- ------- ------- Total 14336000 6323322 8012678 Logical Logs 300000 243820 56180 18.7% who prices pts/tb Jun 15 17:54 stuberj pts/tc Jun 16 07:05 berryj pts/td Jun 16 07:33 watkinst pts/te Jun 16 07:37 skaggsk pts/tf Jun 16 07:39 engelkek pts/tg Jun 16 07:39 bishopa pts/th Jun 16 07:40 dennisg pts/ti Jun 15 11:52 hammerm pts/tj Jun 16 08:04 moughond pts/tl Jun 16 07:41 rueggt pts/tm Jun 15 08:13 westbros pts/tn Jun 16 07:41 hoffpowj pts/tp Jun 16 07:45 hellmutk pts/tq Jun 16 07:54 clarka pts/tr Jun 16 08:09 hammd pts/ts Jun 15 08:29 maloned pts/tt Jun 15 08:53 barnesc pts/tu Jun 16 07:56 wessonc pts/tw Jun 16 07:59 daviss pts/tx Jun 16 08:12 deyoungj pts/ty Jun 16 08:08 jonesa pts/tz Jun 16 08:14 sarverl pts/tA Jun 16 08:09 murleyt pts/tB Jun 16 08:09 mcgheeb pts/tC Jun 16 09:06 hammerm pts/tD Jun 16 08:16 hoodm pts/tE Jun 16 08:19 ackerk pts/tF Jun 16 09:24 keilersv pts/tG Jun 16 08:21 legera pts/tH Jun 16 08:36 hellmutk pts/tI Jun 16 08:23 moughond pts/tJ Jun 16 08:24 smithc pts/tL Jun 16 08:35 weatherb pts/tM Jun 16 10:00 bullardk pts/tN Jun 16 08:44 westbros pts/tO Jun 16 08:42 ardend pts/tP Jun 16 11:16 tilleryl pts/tQ Jun 16 09:13 childree pts/tR Jun 16 08:47 mccalluj pts/tS Jun 15 10:17 dickersd pts/tT Jun 15 10:21 westbros pts/tU Jun 16 12:01 royek pts/tV Jun 16 09:22 edwardje pts/tW Jun 16 10:26 dickersd pts/tX Jun 15 10:25 burrowsr pts/tY Jun 16 09:44 harperk pts/tZ Jun 16 09:28 reedd pts/t2 Jun 16 11:28 bradfork pts/t3 Jun 16 10:01 bakerl pts/t4 Jun 16 10:52 rueggt pts/t5 Jun 15 11:30 waltonj pts/t7 Jun 16 11:40 holleyj pts/t8 Jun 16 10:46 prices pts/t9 Jun 16 10:44 holleyj pts/tab Jun 16 11:31 erpeldic pts/tbb Jun 16 11:32 powellc pts/tdb Jun 16 11:47 Database Status Informix Dynamic Server Version 7.31.UD6 -- On-Line -- Up 18 days 00:03:58 -- 415112 Kbytes Userthreads address flags sessid user tty wait tout locks nreads nwrites d11cc018 ---P--D 1 root - 0 0 0 3496 24626 d11cc520 ---P--F 0 root - 0 0 0 0 508061 d11cca28 ---P--F 0 root - 0 0 0 0 386810 d11ccf30 ---P--F 0 root - 0 0 0 0 354661 d11cd438 ---P--F 0 root - 0 0 0 0 337935 d11cd940 ---P--F 0 root - 0 0 0 0 388000 d11cde48 ---P--F 0 root - 0 0 0 0 388613 d11ce350 ---P--F 0 root - 0 0 0 0 281473 d11ce858 ---P--F 0 root - 0 0 0 0 161051 d11ced60 ---P--- 14 root - 0 0 0 0 816 d11cf268 ---P--B 15 root - 0 0 0 1941 3472 d11cf770 Y--P--- 255079 carsu tg d68d3fb8 0 1 555 0 d11cfc78 Y--P--- 253225 prices tb d40d6c78 0 1 20 0 d11d0180 ---P--D 21 root - 0 0 0 0 0 <SNIP> d5be60e0 Y--P--- 256093 ackerk tF d488eac0 0 1 0 0 278 active, 384 total, 380 maximum concurrent Profile dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached 61252555 63656511 38272855 0.00 4388404 8766681 84453462 94.80 isamtot open start read write rewrite delete commit rollbk 3701808677 65244515 301778893 2584721159 65058168 1805574 587069 560468 1814 gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs 0 0 0 0 0 0 0 ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes 1065 0 0 325269.04 13615.07 1298 3452 bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans 9670592 339 420679365 0 0 183 114309 8420667 ixda-RA idx-RA da-RA RA-pgsused lchwaits 15789770 1108760 29257518 46141844 30166786 Database Locks --------- LISTLOCK: Lock Listing for cars database --------- Table Level Type User Ses ID ---------------------- ------------- ------------------------ ---------- ------ cars.prog_enr_rec row:0x13f005 SR carsu 246346 cars.prog_enr_rec table intent-shared carsu 246346 cars.stufa_rec row:0xe4d01 update carsu 255076 cars.stufa_rec table intent-exclusive carsu 257326 cars.stufa_rec table intent-exclusive carsu 255062 cars.stufa_rec row:0x106f05 update carsu 255078 cars.stufa_rec row:0x120103 update carsu 254986 cars.stufa_rec table intent-exclusive carsu 254986 cars.stufa_rec row:0x116d03 update carsu 260351 cars.stufa_rec table intent-exclusive carsu 255076 cars.stufa_rec table intent-exclusive carsu 255144 cars.stufa_rec table intent-exclusive carsu 260351 cars.stufa_rec table intent-exclusive carsu 255078 cars.stufa_rec row:0x111f01 update carsu 257326 cars.stufa_rec row:0xfe801 update carsu 255144 cars.stufa_rec row:0x12ee07 update carsu 255062 cars.sysdistrib page:0xc5400 intent-shared carsu 255062 cars.sysdistrib page:0xc5400 intent-shared carsu 255076 cars.sysdistrib page:0x1300 intent-shared ackerk 258640 cars.sysdistrib table intent-shared carsu 255078 cars.sysdistrib table intent-shared keilersv 257987 cars.sysdistrib page:0xc5400 intent-shared keilersv 257987 cars.sysdistrib page:0x1300 intent-shared carsu 255144 cars.sysdistrib table intent-shared burrowsr 258393 cars.sysdistrib table intent-shared edwardje 259145 cars.sysdistrib table intent-shared ackerk 258640 cars.sysdistrib page:0xc5400 intent-shared edwardje 258099 cars.sysdistrib table intent-shared carsu 255062 cars.sysdistrib page:0x1300 intent-shared carsu 255076

Thanks all, I hadn't thought about an overflow. Chris S. Support Inf.... wrote: > Yes, we have the same on IDS7.31 > seems to be normal, overrun of some internal profile counters. > So you have to reset the counters once week or so : onstat -z > > Yves > > -----Original Message----- > From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] > Sent: 18 June 2006 05:55 > To: ids@iiug.org > Subject: Cached reads going to 0.00% [6973] > > I've noticed this a couple of times in onstat, for no apparent reason cached > > reads go from 95% or so to 0.00% and then slowly build back up to 95% over > the > next 24hours or so. There's a cronjob that runs at 8, noon, 5 and midnight > that records a few interesting statistics on the machine. We're running > Informix 7.31.UD6 upgrading to a 9.4 on HPUX 11i. The hardware is a little > old > and we have had problems with disk failures in the recent past, any clues? > > Chris S. > > Noon stats run: > > Uptime > > 12:05pm up 18 days, 5 mins, 57 users, load average: 0.46, 0.41, 0.41 > > Free Disk Space > > Filesystem kbytes used avail %used Mounted on > /dev/vg00/lvol3 143360 88747 51249 63% / > /dev/vg00/lvol1 159509 40391 103167 28% /stand > /dev/vg00/lvol8 2048000 1541798 477349 76% /var > /dev/vg00/lvol7 2048000 1894310 144902 93% /usr > /dev/vg00/lvol4 524288 127645 377515 25% /tmp > /dev/vg00/lvol6 2457600 1888515 533739 78% /opt > /dev/vg00/lvol12 155648 1141 144858 1% /opt/perl5 > /dev/vg00/lvol19 1024000 889055 126530 88% /opt/informix > /dev/vg00/lvol11 307200 10529 278156 4% /opt/gnu > /dev/vg00/lvol10 1024000 379940 603844 39% /opt/carstrain > /dev/vg00/lvol9 3072000 1589200 1390347 53% /opt/carsi > /dev/vg00/lvol20 3072000 1229736 1729229 42% /opt/carsi/smo > /dev/vg00/lvol13 2048000 334130 1606763 17% /opt/apache > /dev/vg00/lvol5 20480 1114 18161 6% /home > /dev/vg00/lvol14 2457600 1594848 810532 66% /home/carsids > > Database Free Space > > Name KB Size KB Free KB Used Percent > ------------ ------- ------- ------- ------- > root 1024000 668062 355938 34.8% > dbs0 12288000 4632328 7655672 62.3% > temp1 512000 511434 566 0.1% > temp0 512000 511498 502 0.1% > ------------ ------- ------- ------- ------- > Total 14336000 6323322 8012678 > Logical Logs 300000 243820 56180 18.7% > > who > > prices pts/tb Jun 15 17:54 > stuberj pts/tc Jun 16 07:05 > berryj pts/td Jun 16 07:33 > watkinst pts/te Jun 16 07:37 > skaggsk pts/tf Jun 16 07:39 > engelkek pts/tg Jun 16 07:39 > bishopa pts/th Jun 16 07:40 > dennisg pts/ti Jun 15 11:52 > hammerm pts/tj Jun 16 08:04 > moughond pts/tl Jun 16 07:41 > rueggt pts/tm Jun 15 08:13 > westbros pts/tn Jun 16 07:41 > hoffpowj pts/tp Jun 16 07:45 > hellmutk pts/tq Jun 16 07:54 > clarka pts/tr Jun 16 08:09 > hammd pts/ts Jun 15 08:29 > maloned pts/tt Jun 15 08:53 > barnesc pts/tu Jun 16 07:56 > wessonc pts/tw Jun 16 07:59 > daviss pts/tx Jun 16 08:12 > deyoungj pts/ty Jun 16 08:08 > jonesa pts/tz Jun 16 08:14 > sarverl pts/tA Jun 16 08:09 > murleyt pts/tB Jun 16 08:09 > mcgheeb pts/tC Jun 16 09:06 > hammerm pts/tD Jun 16 08:16 > hoodm pts/tE Jun 16 08:19 > ackerk pts/tF Jun 16 09:24 > keilersv pts/tG Jun 16 08:21 > legera pts/tH Jun 16 08:36 > hellmutk pts/tI Jun 16 08:23 > moughond pts/tJ Jun 16 08:24 > smithc pts/tL Jun 16 08:35 > weatherb pts/tM Jun 16 10:00 > bullardk pts/tN Jun 16 08:44 > westbros pts/tO Jun 16 08:42 > ardend pts/tP Jun 16 11:16 > tilleryl pts/tQ Jun 16 09:13 > childree pts/tR Jun 16 08:47 > mccalluj pts/tS Jun 15 10:17 > dickersd pts/tT Jun 15 10:21 > westbros pts/tU Jun 16 12:01 > royek pts/tV Jun 16 09:22 > edwardje pts/tW Jun 16 10:26 > dickersd pts/tX Jun 15 10:25 > burrowsr pts/tY Jun 16 09:44 > harperk pts/tZ Jun 16 09:28 > reedd pts/t2 Jun 16 11:28 > bradfork pts/t3 Jun 16 10:01 > bakerl pts/t4 Jun 16 10:52 > rueggt pts/t5 Jun 15 11:30 > waltonj pts/t7 Jun 16 11:40 > holleyj pts/t8 Jun 16 10:46 > prices pts/t9 Jun 16 10:44 > holleyj pts/tab Jun 16 11:31 > erpeldic pts/tbb Jun 16 11:32 > powellc pts/tdb Jun 16 11:47 > > Database Status > > Informix Dynamic Server Version 7.31.UD6 -- On-Line -- Up 18 days 00:03:58 >