Re: Why?

"Alexander Skwar" <from_at_alexander.skwar.name> wrote in message news:8iowpa5bgf2f.dlg_at_a.skwar.digitalprojects.com...
> Hi!
>
> In the Oracle documentation, it's often suggested to use OFA to design
> where files are located. This suggests to create filesystems /u00, /u01,
> /u02 ...
>
> What I don't get - suppose that my server supports RAID 5.

No database should run RAID5.

>Why would it
> be "better" to have 3 fs (one for each harddisk) instead of having one
> /data filesystem which consists of those 3 harddisks?

Forget the 'one for each hard disk'. It would be a good idea to have multiple mountpoints or directories within a RAID0 array, because it makes sense to logically separate things which are managed differently. Data files from log files, for example. Or either from control files. OFA sought to separate those things from each other, amongst other reasons, for performance, I/O issues... and it is true that with a RAID array, that argument for OFA goes out of the window. But those three types of file still get *managed* differently, and accordinglt there is still an ease-of-management argument for logically distinguishing them from each other, even if physically it all goes a bit iffy.

So yes, OFA is looking a bit redundant when RAID is in the picture. But not totally so, and as a matter of management convenience rather than anything else, it still has a lot of sense behind it.

Regards
HJR
> I could, of course, also use logical volume manager to create one volume
> group and then create /u00, /u01 and /u02 as lv's in this vg. But why? If
> those filesystems would be used to store "ordinary" files, I could see a
> use (eg. backup purposes), but not so in Oracle.
>
> My question: Why use OFA? Where are the advantages compared to having one
> fs which hosts all the datafiles for Oracle?
>
> Alexander Skwar
> --
> Bück dich, Fee. Wunsch ist Wunsch!
Received on Mon Jun 28 2004 - 04:48:03 CDT