Oracle 8i on filesystem.

[meng_1]

Hi all,
I want use filesystem for oracle 8i as the datafile.
please give me some advice on
this.
I know a lot of people use raw lv to storage the oracle data.
but someone told me that we can get high performance use filesystem. :-)

[Alexander M. Ermes]

Hi there.
You should setup your directories according to Oracle Flexible Architecture ( OFA ).
Check Oracle Metalink and your Oracle documentation for that.
Sample :

/unnn/oradata/ORACLE_SID/arch
for offile redolog files

/unnn/oradata/ORACLE_SID/bdump
for alert logs and system traces

/unnn/oradata/ORACLE_SID/cdump
for Oracle coredumps / traces

/unnn/oradata/ORACLE_SID/exp
for exports

/unnn/oradata/ORACLE_SID/imp
for imports

/unnn/oradata/ORACLE_SID/udump
for userdumps

/unnn/oradata/ORACLE_SID/dbs
for datafiles ( tablespaces )

/unnn/oradata/ORACLE_SID/log
for online logs

/unnn/oradata/ORACLE_SID/cntl
for controlfiles


/home/dba/oracle/admin/ORACLE_SID/arch linked to arch dir mentioned above

/home/dba/oracle/admin/ORACLE_SID/bdump as above

/home/dba/oracle/admin/ORACLE_SID/cdump as above

/home/dba/oracle/admin/ORACLE_SID/udump as above

/home/dba/oracle/admin/ORACLE_SID/create for sql scripts to create a database

/home/dba/oracle/admin/ORACLE_SID/exp for scripts and parfiles for exports

/home/dba/oracle/admin/ORACLE_SID/imp for scripts and parfiles for imports

/home/dba/oracle/admin/ORACLE_SID/sql for sql scripts

and so on.
Samples given in OFA.

keep away online logs from offline logs ( separate disks )

keep away index tablespaces from data tablespaces ( separate disks )

Keep control files away from the others

keep your application logs and output files seaparated.

this needs careful planning and may take some time to spread the different databases through the different mountpoints / disks / directories.

Rgds
Alexander M. Ermes

[Bill Hassell]

Putting all the Oracle datafiles and executables on a single filesystem will have a tremendous impact on performance (it will be very slow). As mentioned, there are many different filesystems, each with very specific tasks and some are very write-intensive. These must be stored on separate disks for reasonable performance.

This is not as raw vs. filesystem question, it is a practical disk layout question. Separate the busiest filesystems onto different disks, even different controllers for optimum performance.

[Andreas D. Skjervold]

Hi

In theory the raw device will give you a better performance, but I've read that the actual gain is minimal.

The advantage in using filesystem is the vastly easier administration of the database such as tablespace growth.

So go with Ernest suggestion, the OFA std. to spread the different part of Oracle on different mountpoints, ofcourse being on different disk drives.

Andreas

[Jason VanDerMark]

The OFA standard is pretty good, but as it was already mentioned, it is not a good idea to put your most I/O intensive things into a single filesystem. I would suggest modifying the OFA by making secondary archives(gzipped archives, make DBAs all warm and fuzzy), secondary tablespace area(allows you to split the heavy hit tables on seperate filesystems.)
and even secondary index area(again for splitting up I/O). I hope that this helps.

Regards,
Jason V.

[Wodisch]

Hello,

since you asked for "filesystem", I guess you want to know the special mount-options for the "Online" or "Advanced" JFS/VxFS:
mincache=direct,convosync=direct
are very useful if (and only if) you only have Oracle-datafiles stored on that filesystem - nothing else, no tracefile/textfile/codefiles, etc!
What happens, is that you avoid the so-called "double-buffering" of the Oracle-datablocks (from Oracle-SGA to UNIX-buffercache to disk), which saves a lot of RAM (and a little time). Then you dedicate that RAM to Oracle and THEN you are much faster :-)

Just my $0.02,
Wodisch