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Re: How to confirm 'direct io' on linux?

From: NetComrade <netcomradeNSPAM_at_bookexchange.net>
Date: Thu, 25 Aug 2005 19:50:41 GMT
Message-ID: <430e2096.105923843@localhost> 





On Thu, 25 Aug 2005 00:21:35 GMT, Mladen Gogala <gogala_at_sbcglobal.net>
wrote:



>On Tue, 23 Aug 2005 20:21:23 +0000, NetComrade wrote:

>

>> We are currently testing running Oracle 9.2.0.6 on Redhat 4.0 AMD x64.

>> We are using Veritas File System, and ODM.. 

>> We have linked odm.so files into $oracle-home/lib

>> On solaris, I believe OS calls should've been ODM, or at least kaio

>> (when using truss), what should we be seeing on linux when using

>> strace?

>

>open(....,O_DIRECT) is what you should see. Direct I/O on Linux is

>available on Ext3 and JFS which are free. I haven't tested VxFS 

>but I can not imagine that it would not perform direct I/O when

>instructed to do so. Here is how you check:

>$ svrmgrl

>

>SQL*Plus: Release 10.2.0.1.0 - Production on Wed Aug 24 20:13:24 2005

>

>Copyright (c) 1982, 2005, Oracle.  All rights reserved.

>

>Connected to an idle instance.

>

>SQL> startup mount

>ORACLE instance started.

>

>Total System Global Area  243269632 bytes

>Fixed Size                  1218748 bytes

>Variable Size              71305028 bytes

>Database Buffers          167772160 bytes

>Redo Buffers                2973696 bytes

>Database mounted.

>SQL> !ps -ef|grep dbw

>oracle    4681     1  0 20:13 ?        00:00:00 ora_dbw0_10g

>oracle    4703  4672  0 20:13 pts/0    00:00:00 /bin/ksh -c ps -ef|grep dbw oracle    4707  4703  0 20:13 pts/0    00:00:00 grep dbw

>

>SQL> Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

>With the Partitioning, OLAP and Data Mining Scoring Engine options

>$

>$ strace -o /tmp/dbwr.out -p 4681 & (Process 4681 is the database writer)

>[1] 4708

>$ Process 4681 attached - interrupt to quit

>

>$

>

>$ svrmgrl

>

>SQL*Plus: Release 10.2.0.1.0 - Production on Wed Aug 24 20:15:33 2005

>

>Copyright (c) 1982, 2005, Oracle.  All rights reserved.

>

>

>Connected to:

>Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

>With the Partitioning, OLAP and Data Mining Scoring Engine options

>

>SQL> alter database open;

>

>Database altered.

>

>SQL> select count(*) from scott.emp;

>

>  COUNT(*)


>----------

>        14

>

>SQL>


>$ grep O_DIRECT /tmp/dbwr.out

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_system_1j2cfzfv_.dbf", O_RDONLY|O_DIRECT|O_LARGEFILE) = 19

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_system_1j2cfzfv_.dbf", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 19

>fcntl64(19, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_undotbs1_1j2cfzm4_.dbf", O_RDONLY|O_DIRECT|O_LARGEFILE) = 20

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_undotbs1_1j2cfzm4_.dbf", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 20

>fcntl64(20, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_sysaux_1j2cfzgq_.dbf", O_RDONLY|O_DIRECT|O_LARGEFILE) = 21

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_sysaux_1j2cfzgq_.dbf", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 21

>fcntl64(21, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_users_1j2cfzmf_.dbf", O_RDONLY|O_DIRECT|O_LARGEFILE) = 22

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_users_1j2cfzmf_.dbf", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 22

>fcntl64(22, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_perfstat_1j2f56l5_.dbf", O_RDONLY|O_DIRECT|O_LARGEFILE) = 23

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_perfstat_1j2f56l5_.dbf", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 23

>fcntl64(23, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_indx_1j2ft1ov_.dbf", O_RDONLY|O_DIRECT|O_LARGEFILE) = 24

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_indx_1j2ft1ov_.dbf", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 24

>fcntl64(24, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_temp_1j2cjwbg_.tmp", O_RDONLY|O_DIRECT|O_LARGEFILE) = 25

>open("/oradata/10g/oracle/datafile/10G/datafile/o1_mf_temp_1j2cjwbg_.tmp", O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE) = 25

>fcntl64(25, F_GETFL)                    = 0xd002 (flags O_RDWR|O_SYNC|O_DIRECT|O_LARGEFILE)

>$

>




What should I _not_ be seeing?


I assume I should be seeing some 'open' command on datafiles.. but I
am not.. this is all i see on mount:


rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0

rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 370000}},
NULL) = 0



rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
semop(8683522, 0x1, 548682064640)       = -1 EINTR (Interrupted system
call)


--- SIGALRM (Alarm clock) @ 0 (0) ---


rt_sigprocmask(SIG_BLOCK, [], NULL, 8)  = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 10000}},
NULL) = 0



rt_sigprocmask(SIG_UNBLOCK, [], NULL, 8) = 0

rt_sigreturn(0x1)                       = -1 EINTR (Interrupted system


call)


rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0

rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={3, 0}}, NULL) =
0


rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
semop(8683522, 0x1, 548682064640)       = -1 EINTR (Interrupted system
call)


--- SIGALRM (Alarm clock) @ 0 (0) ---

rt_sigprocmask(SIG_BLOCK, [], NULL, 8)  = 0
rt_sigprocmask(SIG_UNBLOCK, [], NULL, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0

rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={3, 0}}, NULL) =
0


rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
semop(8683522, 0x1, 548682064640)       = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0


rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0

umask(0)                                = 022


open("/u01/app/oracle/product/920/dbs/lkFOTC", O_RDWR|O_CREAT|O_EXCL,
0660) = -1 EEXIST (File exists)


open("/u01/app/oracle/product/920/dbs/lkFOTC", O_RDWR) = 12

umask(022)                              = 0


fcntl(12, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) =
0


fcntl(12, F_SETLK, {type=F_RDLCK, whence=SEEK_SET, start=0, len=0}) =
0


write(12, "DO NOT DELETE THIS FILE!", 24) = 24
semctl(8683522, 37, SETVAL, 0x1)        = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={1, 640000}},
NULL) = 0



rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
semop(8683522, 0x1, 548682064640)       = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0

rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={1, 640000}},
NULL) = 0



rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
semop(8683522, 0x1, 548682064640)       = -1 EINTR (Interrupted system
call)


--- SIGALRM (Alarm clock) @ 0 (0) ---

rt_sigprocmask(SIG_BLOCK, [], NULL, 8)  = 0
rt_sigprocmask(SIG_UNBLOCK, [], NULL, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0

rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0


setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={3, 0}}, NULL) =
0


rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0
semop(8683522, 0x1, 548682064640)       = 0
rt_sigprocmask(SIG_BLOCK, [ALRM], NULL, 8) = 0
setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 0}}, NULL) =
0


rt_sigprocmask(SIG_UNBLOCK, [ALRM], NULL, 8) = 0

ioctl(9, 0x56584f1c, 0x7fbfffdba0)      = 0
ioctl(9, 0x56584f1c, 0x7fbfffdba0)      = 0
ioctl(9, 0x56584f1c, 0x7fbfffdba0)      = 0
ioctl(9, 0x56584f1c, 0x7fbfffdd70)      = 0
ioctl(9, 0x56584f1c, 0x7fbfffdd60)      = 0
ioctl(9, 0x56584f1c, 0x7fbfffdd60)      = 0


.......


We use Oracle 8.1.7.4 and 9.2.0.6/7 on Solaris 2.7 and RH4
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Received on Thu Aug 25 2005 - 14:50:41 CDT












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