Re: 2GB or not 2GB (datafile limit)? That is the question.

  • From: JApplewhite@xxxxxxxxxxxxx
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Fri, 8 Sep 2006 15:01:32 -0500

As I said, there wasn't detailed analysis of the situation, but the 
SysAdmin thought that might be the case.  It was on an HPUX server 
connected to an older HP XP512 SAN, which consists of about fourteen 72GB 
RAID5 LUNS.  That's the way it was set up 5 years ago and that's what 
we're stuck with.

Our server group buys SANs, gets the vendor (now IBM) to configure them 
for file storage, then tells us that they're out there.  I've given up 
trying to convince them to include us early on.  Anyway, we have terabytes 
and terabytes of SAN, of which our Oracle databases get plenty, so I can't 
complain too much.  Also, all the Opteron machines we're getting for 
database servers are pretty nice, too.

So, I'll retract my assertion, since I don't really know and don't want to 
start any kind of Oracle Myth.  The 2GB datafile size is still handy for 
all the other reasons I mentioned.

Jack C. Applewhite - Database Administrator
Austin (Texas) Independent School District
512.414.9715 (wk)  /  512.935.5929 (pager)

 I feel so unnecessary.  -- Rufus Thomas
               ( "Do the Funky Chicken")

"Jared Still" <jkstill@xxxxxxxxx> 
Sent by: oracle-l-bounce@xxxxxxxxxxxxx
09/08/2006 11:47 AM
Please respond to

Re: 2GB or not 2GB (datafile limit)? That is the question.

On 9/8/06, JApplewhite@xxxxxxxxxxxxx <JApplewhite@xxxxxxxxxxxxx > wrote:


I don't know about OS issues, but we also stick to a max 2GB datafile size 
for a different reason.  Almost all our servers (Linux and HPUX) are on 
one of our SANs and we've found that the OSs tend to give each mount point 
the same (on average) fraction of I/O bandwidth to the SANs.  This was 
startlingly obvious when, at the recommendation of one of our SysAdmins, 
we put a Production database all under 1 mount point and its performance 
suffered greatly - no detailed analysis, it was just obvious.  When we 
spread that same database across multiple mount points on the same server 
and SAN, performance improved dramatically. 

That seems rather strange.

It likely had more to do with disk configuration rather than the number of 
mount points.
Jared Still 
Certifiable Oracle DBA and Part Time Perl Evangelist

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