RE: Datafile size - Is bigger better?
- From: "Richard J. Goulet" <rgoulet@xxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 15 Nov 2006 10:28:51 -0500
Jay,
I'd say it sorta depends on the application(s) that your hosting and
the hardware your using. Many a company is still not using any type of
SAN/disk management system for one reason or another. Most of them
don't make a lot of sense except that they just don't want to spend the
money. Personally I think the day of the 2GB file max limit is a
dinosaur that just won't lay down & die, like the 90+% cache hit ratio
thing. On the other hand there are some good reasons to limit and not
limit file size. I don't know if too many people are aware that Oracle
imposes a limit of 1024 files per tablespace. If your like a client of
ours that becomes a problem. They decided for various reasons that are
history, that they'd limit files to 1GB. Well their SAP tablespace grew
& grew till it hit that 1024 limit causing a significant "Keystone Cops"
situation. Also Oracle imposes a limit of 2147483645 blocks per data
file.which limits you to 16TB in an 8KB, 8TB with 4K and 4TB in a 2K
system. Granted that still gives one a LOT of space to grow into, but
their out there waiting to bite you at an in-opportune moment as noted
above. Personally I find the argument about how big is your backup
bucket much more compelling. Tapes aren't exactly cheap and the more of
them that you have to search through the longer that recovery is going
to take & the more heat your going to get.
Dick Goulet, Senior Oracle DBA
45 Bartlett St Marlborough, Ma 01752, USA
Tel.: 508.573.1978 |Fax: 508.229.2019 | Cell:508.742.5795
RGoulet@xxxxxxxxxx
: POWERING TRANSFORMATION
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of JayDBA
Sent: Tuesday, November 14, 2006 5:57 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Datafile size - Is bigger better?
Can I trigger a discussion on the pros and cons of datafile max-size. I
am in a shop where the datafile size is limited to 2gb on a 64-bit
platform (Raided) and I am trying to weigh the pros and cons of having a
larger file limit.
Pros:
1. Quicker recovery
2. Easy to load balance
Cons:
1. How often do we have to recover?
2. Is load balancing on the database level really an option for raided
systems
3. On locally managed files, we loose header space equal to the extent
size. E.g. on a datafile with uniform extent sizing of 128M a 2gb file
would waste 6% space / file. This number can run into gigabytes on
systems with 100's of 1000's of files
4. CKPT having to work more since it has to update many more smaller
files.
Regards
Other related posts:
