FWIW, what we just implemented (because senior management refuses to approve
additional storage on the grounds that "making the database larger will
affect performance" - aaargh!) is
1) Confirmed with business how long data needs to be online for various
tables (they're all partitioned so that makes it a lot easier)
2) Export partitions older than that once/month (this is generated off a
table that lists each partitioned table and how long data should be kep)
3) After confirming that all export files are valid we drop the old
partitions (this will be done by script but is being done manually for the
first few months)
4) Leave dmp files on server for 2 end of months (our end of month backup
tapes are stored for 7 years)
5) Maintain a table in database saying what exported partitions are on what
date's tapes
And I really long for the days in this company when senior management made
technical decisions by asking the technical people instead of just making
things up...
Jay Miller
-----Original Message-----
Sent: Wednesday, November 06, 2002 11:54 AM
To: Multiple recipients of list ORACLE-L
Someone asked about this 3 weeks ago. Here's my take
on archiving data. I don't expect everyone to agree with this,
but nonetheless, I have an opinion. :)
Here's an email from last month. You can undoubtedly find
some other ideas on this by searching the archives of this
list at fatcity.com
Jared
==================================================
I'm not a proponent of purging data.
Unless of course, you expect to never see it again.
That word 'archive' rolls of the tongues of managers
and consultants pretty easily, but what's behind it?
There are a few gotchas with purging and archiving.
Let's assume you have some 3 year old data that
you need to see again, and it has been purged.
Here are some of the possible problems:
* Your backup tapes are corrupted
* Your new backup hardware can't read the old tapes
* Your software no longer understands the format that
the data is in.
* You have the correct software, but it won't work on the
current version of OS on your hardware.
* The data format/software/whatever is not well documented
* The employees that understood the data 3 years ago
have been laid off.
* ... lots more stuff
Read Bryon Bergeron's "Dark Ages II: When the Digital Data Die"
http://www.powells.com/cgi-bin/biblio?inkey=2-0130661074-0
Perhaps much better than archiving the data, is to stick with the
idea of moving it to another database, and using lots of cheap
disk storage (NAS) or a heirarchical file system to store it.
The point being that if it's online somewhere, it will be maintained.
Don't purge it till Finance, HR, the IRS and any other stakeholder
says it's ok. Only then purge it and archive it to offline tape with the
knowledge that you may never see that data again.
Jared
[EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
11/06/2002 01:13 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
cc:
Subject: Data Purging Strategy
Dear List,
I need some inputs from you all regarding purging data from the database.
This is the requirement
We define a retention period for all the data in the system.
When the retention period is reached, the data should be deleted, but
then at a later time, some user might request for this purged data. So it
must be possible to retrieve this data.
This is the strategy we have designed for this.
When the retention period is reached, move the data from the main database
to an offline database. Then delete the data from the main database.
In the offline database, we cannot again keep it from long, so it has to
moved to tapes. Now my question, how can we move this data to tapes and at
the same time retrieve data from the tapes based on dates.
i.e, the user will ask for the data on a particular date, so it must be
possible to retrieve data from the tapes based on a date and load it to
the database tables.
Regards
Prem
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