Fallback & Down Amp recovery journal!!!


Fallback & Down Amp recovery journal!!!


When a Fallback protected AMP goes down during a write operation, the update takes place
in the Fallback AMP in the same cluster to later update in the original AMP when it recovers.

When an AMP goes down the updates are also recorded in the Down AMP Recovery journal to later update when AMP recovers.

My doubt is when an AMP goes down are the updates made in both Fallback AMP & Down AMP recovery journal?

Because if Yes, it looks like a redundant recovery measure or
Is it like Down AMP Recovery journal is used for only Non Fallback protected AMPs or
for Fallback protected AMPs when both the AMPs in the cluster are down.

Annal T

Re: Fallback & Down Amp recovery journal!!!

Hi Annal,
According to my knowledge
1.Down amp recovery journal will start when AMP goes down to restore the data for the down amp
2.fall back is like it has redundant data,if one amp goes down in the cluster also it wont affect your queries.the query will use data from fall back rows.the down amp wont be updated use the data from fall back.

For your doubt,When amp is down you ran the update,so fall back rows will be updated.Still amp is in down condition and if you run the query,the query will use the updated ones and run.whenever down amp active it will use downamp recovery journal and data will be updated.

Hope this helps.

Syam Prasad K