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How to estimate the size of journal volume in RP for CRR only
I need to configure RP for my client as CRR only.
I simplify details as below:
CRR only
Source lun = 1TB
Size of daily change (1TB * 15%) = 150GB
Only one consistency group for this source lun. No other consistency group.
RTO = 1hrs
RPO = 48hrs
How to estimate the journal volume? And any overhead need included?
Hope all of you feedback.
Thanks!
etaljic81
1K Posts
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November 15th, 2011 06:00
The best way to do this is by looking at performance data and running it through a tool called BCSD. However, if you don't have access to the tool you can use the attached image to calculate the journal size.
ASL-Mike
18 Posts
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November 15th, 2011 07:00
Ernes,
Thanks for your reply.
Can you tell me which RP document I can find this forumla?
Mike
etaljic81
1K Posts
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November 15th, 2011 07:00
I don't think that's available in the latest RP docs. I took a screenshot of the formula from one of the older RP docs and saved it on my computer
etaljic81
1K Posts
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November 15th, 2011 08:00
No problem. The good news is that a consistency group can have more then one journal volume. So if you find that your protection window is not holding as many PIT images as you want you can add another LUN to the CG as a journal volume.
ASL-Mike
18 Posts
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November 15th, 2011 08:00
Anyway, thanks.
SKT2
1.3K Posts
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November 27th, 2011 13:00
you have your RTO and RPO values interchnaged ( RPO is lesser than RTO ); RPO represents affordable window of DATA LOSE, while RTO is recovery time.