I am afraid it can be much more complex than this. I'm not an expert on
this, but let me take a stab at it...
Do you need to replicate synchronously? If so, latency is going to be a
critical consideration.
How much lag can you tolerate? If you base estimates on "hourly" redo
rates, I can easily picture lags of an hour or two. If your estimate is
based on an "average" hourly rate, lags of many hours (during/following
peak periods) are not unlikely.
Are your data volumes subject to seasonal fluctuations? If so, you will
want to size for your peak season.
If you want to set up a standby with a reasonable expectation of not
(often) lagging by more than 5 minutes, then you need to identify the
amount of redo generated in your busiest 5-minute interval (or maybe 90th
percentile, if you want to save some money and can live with occasionally
missing your SLA) and size your network to support that.
You also want to ensure that the bandwidth you specify is *guaranteed* to
be available to your replication traffic. It benefits you nothing to size
the bandwidth properly, and then have it all chewed up by people watching
funny cat videos on youtube.
On Wed, May 13, 2015 at 9:32 AM, George <georgelza@xxxxxxxxx> wrote:
I work it out another way...
Determine redo creation a hour, and then ask Networks to provide the
required bandwidth to transfer that volume in a hour.
You can use the redo log generation over 24 hours to draw a graph, showing
how it goes up and down and give them the required rate per hour.
G
On Wed, May 13, 2015 at 3:29 PM, max scalf <oracle.blog3@xxxxxxxxx> wrote:
Hello list,
we are in process of deploying a Data guard and i am looking to get a
bandwidth requirements. While googleing i came across the below formula
multiple times..my question is what exactly do the below numbers represents
0.7, 8, 1000000 ?? i know we can get and redo rate bytes per sec from
v$sysmetric_history but confused on the numbers...
*Required bandwidth = ((Redo rate bytes per sec. / 0.7) * 8) / 1,000,000
= bandwidth in Mbps *
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