Thanks for the question, Saivishnu.
Asked: January 07, 2020 - 6:26 am UTC
Answered by: Connor McDonald - Last updated: January 22, 2020 - 2:55 am UTC
Category: Database Administration - Version: 11.2.0
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Hi,we have 1 TB datafile in a diskgroup with normal redundancy. We are planning to move that datafile to another diskgroup with external redundancy. The reason for that is because we have a huge diskspace consumption and if we get rid of redundancy, then we will save half the space. We would like to know the time required to move that 1 TB datafile to another diskgroup. Is there a mechanism available to find out an approximate time required to move the datafile from 1 diskgroup to another. We need to complete the activity in 30 minutes.
and we said...
It will take...
....this long :-)
Jokes aside, it depends on your storage hardware, your CPU power, concurrent usage, number of disks, cache overhead, etc etc etc etc..... Moving a terabyte could take anything from 1min to 1 month.
But....the BEST person to know how long it will take is YOU.
- create a 1gig datafile, and move that, and time it
- create a 10gig datafile, and move that, and time it
- create a 50gig datafile, and move that, and time it
And then you'll have a very good estimate of what a terabyte will take.
But mirroring can be controlled at the file level, so perhaps an option for you currently is:
- Leave existing files in the current (mirrored) disk group, but set them to un-mirrored at the file level. That frees up some space
- Wait until you upgrade to 12c, at which point you can move files around with no outage at all.
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