MemberJune 10, 2020 at 4:30 pm
Scenario: “An online bank portal is using Amazon ElastiCache for Redis as its distributed session management layer as well as to store database queries which are expensive to perform.”
one answer states: “Schedule automatic backups of the cluster which writes all data from the cache to a Redis RDB file.”
explanation: “[this answer] is incorrect because the data loss potential for daily scheduled backups is high – up to a day’s worth of data.”
But there’s nothing stated about doing the backup only once a day…
“During any contiguous 24-hour period, you can create no more than 20 manual backups per node in the cluster.” https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/backups.html#backups-constraints
“The minimum length for the backup window is 60 minutes.” https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/backups-automatic.html
(I didn’t find anything specific about the limit on amounts of automatic backups per day)
In case you could combine a regular backup (few times a day) with AOF, that would be a good solution also, and probably cheaper (but this option is unfortunately not given!)
Nevertheless the multi-az is thus the better solution in the given situation.
I would suggest to improve the explanation a bit though.
MemberJune 12, 2020 at 10:32 pm
Thank you for your inputs.
I think the “once-a-day” backup pertains to the default automatic daily backup on which the explanation was focused on.
I agree that we should improve the explanation part of this question.
You can adjust the default and schedule multiple backups per day. But that will still result in data loss in between the intervals of those backups.
We can revise the explanation to better make this point across.
Thanks and regards,
Kenneth Samonte @ Tutorials Dojo
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