Re: Oracle-managed RAID-like tablespaces

On Sun, 28 Jul 2002 12:09:56 +0200, Rick Denoire <100.17706_at_germanynet.de> wrote:

>Hello all DBAs out there
>
>Not sure, but I seem to have read somewhere that there is the
>possibility in Oracle to set up tablespaces that would span several
>independent harddisks. Of course, one can always do that adding
>additional files in the corresponding harddisks, but that is not what
>I mean.
>
>I mean that Oracle would automatically spread data of a segment over
>several independent harddisks in a way that they are not put
>physically in a sequencial order in one file/disk, but building
>"stripes" over a group of disks.
>
>If this feature really exists, then doing a full table scan would
>cause to distribute read requests over several disks, even if they are
>organized as JBOD ("just a bunch of disks") instead as a real RAID,
>but effectively, read performance would compare to that of a RAID. I
>am assuming that in this situation Oracle would not wait for a read
>request to complete in order to demand the next request (asynchronous
>reading). I think that for this Oracle's own stripe management, files
>put in different disks should have the same size, of course.
>
>And by the way, this feature allows a harddisk to behave as a part of
>a RAID while at the same time sequential writes to just this one
>particular disk would still be possible (for redologs, for example),
>without disturbing "RAID-like" read requests of other disks! (Remember
>that in a hardware RAID, one has no control about the physical layout
>of data on disks other than determining the stripe width and RAID
>level at setup time).
>
>Too good to be true. Am I just dreaming or what? Please correct me!
>
>I am interested in using this feature, if it exists, because we are
>setting up a cheap test environment without RAID.
>
>Thanks
>Rick

Please read the Oracle Myths thread in this newsgroup and download the SAME (Stripe And Mirror Everything) whitepaper from Metalink.

Hth

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Sun Jul 28 2002 - 05:35:50 CDT