Re: Out of morbid curiosity - can you straddle datafiles using Filesystem + ASM DGs
- From: Mladen Gogala <gogala.mladen@xxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Thu, 20 Jun 2019 17:43:16 -0400
On 6/20/19 5:15 PM, Chris Taylor wrote:
I'm mainly just curious as we need to move a 100TB database to ASM and
have limited storage capacity and was wondering if this would be an
option.
Well, that depends on the ASM redundancy. To move 100TB db to ASM with
external redundancy, you need at least 100TB storage. With normal
redundancy, it's at least 200TB and with abnormal redundancy (does
anyone remember "Young Frankenstein"?) , it's at least 300 TB. You can
also move 100TB database to 20 TB storage, but you would have to do a
lot of "TRUNCATE" and "DROP" commands which are usually not highly
regarded by the business owners of the database.
Where you would have the ASM DGs available to the DB and datafiles on
Filesystems.
Then slowly move datafiles (alter database datafile move) over to the
ASM diskgroups and reclaim the filesystem volumes as we free them up.
Again, this is really out of morbid/technical curiosity more than
anything.
Chris
There is another option, called "ACFS" which also runs on top of ASM and
technically satisfy all of your requirements. You can have data files on
ACFS and non-ACFS file systems, in the same database.
--
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
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