Re: EMC Data Deduplication
- From: Hemant K Chitale <hemantkchitale@xxxxxxxxx>
- To: jrkhym@xxxxxxxxx
- Date: Fri, 5 Nov 2010 18:20:38 +0800
RMAN Incremental doesn't need BCT to reduce the size of the Backup file. It
uses BCT to improve the performance of the backup -- BCT helps identify the
modified blocks.
If the number of blocks modified since the last backup is a very large
proportion of the total size, then the Incremental Level 1 backup would
still be nearly as large as the L0 backup.
So what matters is the number of modified blocks.
Deduplication may also find that a large portion of the database has been
modified !
Hemant K Chitale
On Fri, Nov 5, 2010 at 5:55 PM, Jason Khym <jrkhym@xxxxxxxxx> wrote:
> I am an oracle DBA at a large ulitity company in the Southeastern US. Our
> IT shop is considering buying this product for our server,email and database
> backups. It would replace Veritas Netbackup Server and Tape libraries. I
> was wondering if anyone on the list has any experience with the product.
>
> We current at taking full level 0 hot backups on all of our production
> databases every night. So I know a dedup product like this would save us
> alot of backup space. I also realize that RMAN incremental backups with
> Block Change Tracking would give us the same benefit with less cost. We
> haven't had time to implement this as a backup standard yet. Our db engineer
> tried using incremental backups back in 8i or 9i and said it was not
> reducing the backup size. He later found out he needed to enable BCT to see
> the full size reduction. Our IT engineers want us(DBAs) to write RMAN
> backups directly to this dedup servers. I am not sold on that idea. I would
> like to continue to write our backup to ATA SAN storage and have the backups
> pulled to the dedup devices.
>
> Overall, what do you think of this product? Any gotchas or leasons learned
> that can be shared?
>
--
Hemant K Chitale
http://hemantoracledba.blogspot.com
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