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April 28th, 2011 23:00

How much storage should be allocated for the replication

Hi,

Could please explain me how to calculate following. We know the answer but don't know hoe to calculte it.

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Q: 165 An application uses ten 10 GB Devices. A pointer based replica of the
application is required. The replica will be kept for 24 hours. The data changes by 20% every 24 hours. How much storage should be allocated for the replication?

Answer:-  20 GB

An application uses ten 20 GB devices. A full volume replica of the application is required. The replica will be kept for 24 hours and the data changes by 20% every 24 hours. How much storage should be allocated for the replication?

Answer:- 40 GB

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Q: 19 An application uses ten 9 GB devices. A full volume local replica of the
application is required every 6 hours. Each replica will be kept for 24 hours. How many replica devices are required?

Answer:- 40

Q: 89 An application uses ten 9 GB Devices. A pointer based replica of the
application is required every 4 hours. Each replica will be kept for 24 hours. The data changes by 10% every 4 hours.How many replica devices are required?

Answer:- 60

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Regards,

91 Posts

May 3rd, 2011 12:00

Hello

It's very simple.

q165: 10Gb * 10 dev = 100Gb

you need to keep replica for 24h and amount of changes during 24h is 100Gb * 20% = 20Gb

Next question without number is the same as above

q19: Let's do a simple simulation

First day 0h 0m - system will get ten replica devices

First day 6h 0m - system will get another ten replica devices. Total is 20

First day 12h 0m - system will get another ten replica devices. Total is 30

First day 18h 0m - system will get another ten replica devices. Total is 40

Last step is a bit tricky. If you need exactly 24 hours of protection, you will not replace first set of relica devices with new data until you will successfully create new one:

Second day 0h 0m - system will get another ten replica devices. Total is 50

And just after complition of this step you will delete 10 replica devices with data older then 24 hours

In real replication it depends

If you for example use Celerra checkpoints, it has refresh option when it reuse old checkpoint and answer would be 40

So the right answer is depend of particular exam

91 Posts

May 4th, 2011 04:00

Welcome!

2 Intern

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147 Posts

May 4th, 2011 04:00

Hi,

Thank you very much...It wil be use full for me more learning and establishing new enviroment.

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