Solaris10如何确认DirectIO是否已经启用

对于Oracle而言，如果数据库存储在UFS文件系统上，启用DirectIO能够提高数据库性能。Oracle有个参数filesystemio_options可以控制数据库是否使用DirectIO.  如果在Oracle已经设置了使用DirectIO，怎样才能确认DirectIO是否真起作用了呢？在Solaris10上，可以通过dtrace来确认DirectIO是否已经启用。

1. DirectIO未启用的情况

检查filesystemio_options参数设置

SQL> show parameter filesystem

NAME                                 TYPE                             VALUE
------------------------------------ -------------------------------- ------------------------------
filesystemio_options                 string                           ASYNCH

ASYNCH表示数据库只启用了异步IO, 没有启用DirectIO.

Dtrace检查控制文件是否启用DirectIO

root@ofs001 # dtrace -n io:::start'/(args[0]->b_flags & B_READ) == 0 && args[2]->fi_pathname == "/oracle/data1/ACC010C1/control01.dbf"/{@[stack()] = count()}'
dtrace: description 'io:::start' matched 6 probes
^C

              ufs`lufs_write_strategy+0x100
              ufs`ufs_putapage+0x4f1
              ufs`ufs_putpages+0x308
              ufs`ufs_putpage+0x82
              genunix`fop_putpage+0x28
              genunix`vpm_sync_pages+0xa3
              ufs`wrip+0x6f7
              ufs`ufs_write+0x211
              genunix`fop_write+0x31
              genunix`pwrite+0x14f
              unix`sys_syscall+0x17b
               44

系统调用了ufs_write, 表示DirectIO未启用

Dtrace检查数据文件是否启用DirectIO

在一个session上执行dtrace命令，另一session执行一个create table … as select * from xx;的命令.

root@ofs001 # dtrace -n io:::start'/(args[0]->b_flags & B_READ) == 0 && args[2]->fi_pathname == "/oracle/data2/ACC010C1/users01.dbf"/{@[stack()] = count()}'
dtrace: description 'io:::start' matched 6 probes
^C

              ufs`lufs_write_strategy+0x100
              ufs`ufs_putapage+0x501
              ufs`ufs_putpages+0x308
              ufs`ufs_putpage+0x82
              genunix`fop_putpage+0x28
              genunix`vpm_sync_pages+0xa3
              ufs`wrip+0x6f7
              ufs`ufs_write+0x211
              genunix`fop_write+0x31
              genunix`pwrite+0x14f
              unix`sys_syscall+0x17b
                4

              ufs`lufs_write_strategy+0x100
              ufs`ufs_putapage+0x4f1
              genunix`pvn_vplist_dirty+0x3aa
              ufs`ufs_putpages+0x1c2
              ufs`ufs_putpage+0x82
              genunix`fop_putpage+0x28
              ufs`ufs_fsync+0x1c4
              genunix`fop_fsync+0x28
              genunix`fdsync+0x28
              unix`sys_syscall+0x17b
               20

系统调用ufs_write, 表示DirectIO未启用

2. DirectIO启用的情况

检查filesystemio_options参数设置

SQL> show parameter filesystem

NAME                                 TYPE                             VALUE
------------------------------------ -------------------------------- ------------------------------
filesystemio_options                 string                           SETALL

SETALL表示数据库同时启用了异步IO和DirectIO.

Dtrace检查控制文件是否启用DirectIO

root@ofs001 # dtrace -n io:::start'/(args[0]->b_flags & B_READ) == 0 && args[2]->fi_pathname == "/oracle/data1/ACC010C1/control01.dbf"/{@[stack()] = count()}'
dtrace: description 'io:::start' matched 6 probes
^C

              ufs`directio_start+0x12c
              ufs`ufs_directio_write+0x788
              ufs`ufs_write+0x383
              genunix`fop_write+0x31
              genunix`pwrite+0x14f
              unix`sys_syscall+0x17b
               39

系统调用ufs_directio_write, 表示启用了directio.

Dtrace检查数据文件是否启用DirectIO

在一个session上执行dtrace命令，另一session执行一个create table … as select * from xx;的命令.

root@ofs001 # dtrace -n io:::start'/(args[0]->b_flags & B_READ) == 0 && args[2]->fi_pathname == "/oracle/data2/ACC010C1/users01.dbf"/{@[stack()] = count()}'
dtrace: description 'io:::start' matched 6 probes

^C

              ufs`directio_start+0x12c
              ufs`ufs_directio_write+0x788
              ufs`ufs_write+0x383
              genunix`fop_write+0x31
              genunix`pwrite+0x14f
              unix`sys_syscall+0x17b
               17

系统调用ufs_directio_write, 表示启用了directio.