Ln -s /opt/VRTSodm/lib/libodm.sl $ORACLE_HOME/lib/libodm10.sl Iv) create a soft link to veritas ODM library (* Note 9i library name ie libodm9.so,10g is libodm10.so and 11g is libodm11.so) $ mv $ORACLE_HOME/lib/libodm10.so $ORACLE_HOME/lib/libodm10.so.org $ mv $ORACLE_HOME/lib/libodm10.sl $ORACLE_HOME/lib/libodm10.sl.org Iii) Take a backup of existing original ODM library The following steps to enable/disable ODM for Oracle database (note that with different versions of the Solaris OS, the path may change to the ODM files).
#ORACLE DISK MANAGER DRIVER#
We assume Veritas ODM driver is installed, mounted and available. Oracle uses normal synchronous writes, without “none” – This disables ASYNC IO and DIRECT IO so that “setall” – Enables both ASYNC and DIRECT IO. Will try to use “directio” option for NFS “directIO” – This allows directIO to be used where “asynch” – This allows asynchronous IO to be used where Concurrent I/O performs very close to that of raw logical volumes. It also avoids double buffering by bypassing the filesystem buffer cache and thus improves physical read/write performance significantly. It is the responsibility of the application or the running threads to coordinate the write activities to the same file. This advisory is generally used by applications that require high performance for accessing data and do not perform overlapping writes to the same file. Please note that remount should not be used to enable Concurrent I/O on mounted filesystems.Ĭoncurrent I/O allows multiple processes to read from or write to the same file without blocking other read(2) or write(2) calls.With Concurrent I/O, the read and write operations are not serialized. Mount -F vxfs -o nodatainlog,cio /soevxfs/redos /oracle/mnt/redos To enable Concurrent I/O, the filesystem must be mounted with “-o cio”. Concurrent I/O is available in OnlineJFS 5.0.1. If you set DISK_ASYNCH_IO to false, then you should also set DBWR_IO_SLAVES or DB_WRITER_PROCESSES to a value other than its default of zero in order to simulate asynchronous I/O.Īgain the default setting of ASYNCH can be used when implementing direct I/O on HP-UX / Veritas.Īn alternative solution to Direct I/O is to use Concurrent I/O. If your platform does not support asynchronous I/O to disk, this parameter has no effect. However, if the asynchronous I/O implementation is not stable, you can set this parameter to false to disable asynchronous I/O.
If your platform supports asynchronous I/O to disk, Oracle recommends that you leave this parameter set to its default value. None – This disables ASYNC IO and DIRECT IO so that Oracle uses normal synchronous writes, without any direct io options.ĭocument 120697.1 Init.ora Parameter “FILESYSTEMIO_OPTIONS” Reference NoteĭISK_ASYNCH_IO controls whether I/O to datafiles, control files, and logfiles is asynchronous (that is, whether parallel server processes can overlap I/O requests with CPU processing during table scans).
Setall – Enables both ASYNC and DIRECT IO. Direct IO bypasses any Unix buffer cache.
This allows asynchronous IO to be used where supported by the OS.ĭirectIO – This allows directIO to be used where supported by the OS. This parameter should not normally be set by the user.Īsynch – Set by default on HP. Parameters in Oracle influencing the use of Direct IOįILESYSTEMIO_OPTIONS defines the IO operations on filesystem files. If your filesystem is mounted with this option, then FILESYSTEMIO_OPTIONS default setting of ASYNCH can be used in order to use DIO. However, cases where the disk read could have been avoided because a required block was in file system buffer cache may be negatively impacted. This avoids double buffering by bypassing the file system buffer cache and can improve physical read/write performance. Mincache=direct and convosync=direct allow data to be transferred directly from Oracle buffer cache to disk and disk to Oracle buffer cache. “convosync=direct” => force direct I/O for DB writers ProcList CPU Rpt Mem Rpt Disk Rpt NextKeys SlctProc Help Exit GlancePlus C.04.50.00 19:15:39 bplita3 ia64 Current Avg High - CPU Util S SN NU U | 90% 90% 90% Disk Util F F |100% 100% 100% bypass buffer cache on read (Since the version 10g, Oracle will open data files located on the JFS2 file system with the O_CIO option if the filesystemio_options initialization parameter is set to either directIO or setall.)ĭisk utility output shows 100% usage for disk continously: 简单来说对于Veritas Vxfs和ODM FILE而言filesystemio_options不生效(This parameter is not applicable to VxFS files, ODM files, or Quick I/O files.)，必要检查ODM SO是否正确LINK。
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