The first question I'd ask is how near is near? What's the business driver
for "near"? That will help answer my second question which is essentially,
how much are you prepared to pay?
On Fri, Sep 23, 2022 at 6:56 PM Chris Taylor <
christopherdtaylor1994@xxxxxxxxx> wrote:
Right for guaranteed 0 Data Loss it would have to be Max Protection -
because you've got transfer latencies every where else.
I don't think they'd swallow the standby going down is going to bring down
production.
The AWS snapshot copy and replication honestly looks like a better tool
for "near" 0 than other dataguard options *if* Amazon can replicate those
snapshots very fast at the storage level.
As only the changes are applied that have occurred on disk (which will
include online logs that are changing).
Problem is, of course, I don't know how fast that transfer *can occur *between
regions _and_ I'm not clear on how often I can schedule the snapshots -
every minute, or less? Or every 5 minutes or more? Some black holes there.
Its a very similar idea to the way we used to use SAN replication between
data centers where any data center had the volumes ready to be mounted if
the primary went down.
No licensing fees because Oracle isn't installed on any of the remote
machines until the volume is mounted , at that point Oracle is there and
considered licensable.
I loved those setups.
Chris
On Fri, Sep 23, 2022 at 12:50 PM Tim Gorman <tim.evdbt@xxxxxxxxx> wrote:
Chris,
Whether you're on-prem or in cloud...
- RAC, RAC one-node, and OS-level HA clusters (i.e.
Pacemaker/Corosync, etc) provide protection only to the *database *
*service*, not to the *data* in the database
- RPO isn't a factor with service protection, as RPO is a characteristic
of *data protection*
- Restore/recovery from database backups can not guarantee RPO lower
than the initialization parameter setting for ARCHIVE_LAG_TARGET
- ...and there are many reasons to consider RPO to be at least
twice the ARCHIVE_LAG_TARGET value as well...
- Data replication utilities like GoldenGate, SharePlex, etc
cannot guarantee RPO=0 due to all the queuing and forwarding necessary
- "*eventual consistency*" also implies that "*eventual*" could
turn out to be "*never*"
The only Oracle mechanism which guarantees RPO=0 is DataGuard using MAX
PROTECTION mode, while DataGuard in MAX AVAILABILITY mode comes in with a
close second.
Even the Zero Data Loss Recovery Appliance (ZDLRA) essentially employs
the same mechanisms used by DataGuard MAX PROTECTION mode.
Please let me know what you think?
Thanks!
-Tim
On 9/23/2022 3:51 AM, Chris Taylor wrote:
Hey guys, recently started working at a new company that's moving their
Oracle database to AWS.
One of the things they want is a near-0 RPO.
I was looking into AWS snapshot and replication to accomplish this which
seems pretty doable.
Either in the same region or into another region in case the region was
down/unavailable.
So I'm looking for two things:
1.) Other options? Active-Passive setup in 2 different regions? (Like
Failover but non-RAC)
2.) Anyone using AWS and snapshot copies & replication for Oracle in AWS?
Reference:
(Taking snapshots)
https://aws.amazon.com/blogs/database/improving-oracle-backup-and-recovery-performance-with-amazon-ebs-multi-volume-crash-consistent-snapshots/
(Replicating Snapshots)
https://aws.amazon.com/blogs/aws/ebs-snapshot-copy/
Thanks,
Chris
