FW: [Fwd: Re: Large exports on NT]

Micheal,

> Why would it be any faster to get 8 x 2GB datafiles from tape
> for a tablespace than 1 x 16GB one?

Only for the case of where you lose one datafile (say from a writefile() error from a RAID controller) so you then only need to bring one datafile back from tape, and recover the one datafile, not the entire database.

RMAN does allow for parallelization, so there can be benefits for having multiple datafiles for backup and restore, if you are backing up to disk or multiple tape drives.

Single tape drive, no difference betwee 8 x 2 GB or 16 x 1 GB - limited by write/read rate of tape device.

If you have enough disks, there's some improvement in performance by having multiple datafiles for that tablespace on different disks (different controllers ... I'm dreaming) - obvious stuff, nothing new. I wonder if there is any latch contention improvements if you have multiple datafiles.

Heading off topic, but one other thing - if you have multiple datafiles in your Rollback Segments (for example) tablespace and one datafile goes offline, you still have other rollback segments available to handle transactions.

liking lots of smaller datafiles ...

Paul

• Original Message -------- Subject: Re: Large exports on NT Date: Fri, 10 Nov 2000 10:22:55 -0800 From: "Michael Ray" <Michael.Ray_at_trw.com> Reply-To: ORACLE-L_at_fatcity.com Organization: Fat City Network Services, San Diego, California To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>

I thought the NTFS limit was much larger than that (at least 2TB). We have a 16GB datafile that we have exported and imported on SP5. Why would it be any faster to get 8 2GB datafiles from tape for a tablespace than 1 16GB one?

Michael Ray
Oracle DBA
TRW, Marshall, IL
217-826-3011 x2438

>>> drake_at_psscorp.com 11/10/00 10:15AM >>> Hi.

NT Server 4.0 has a hard limit (NTFS) of 16 GB. Funny how we found that one out ... it turned out to be the brakes for a temporary tablespace's datafile on a runnaway process.

What version of Oracle - I know with 8.1.6 you can tell exp to use multiple
files of a certain slice size ...

Getting off-track here, but I can't think of any reason that anyone would
ever want to think about having a 16 GB datafile, through. How long to get
tht back from tape?

hth,

Paul

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