A potential customer is evaluating an EMC Avamar system as a backup solution. After initial
sizing, they added a requirement to encrypt all backup data on the Avamar system. The original
sizing documents indicated that the customer required 54 TB of storage capacity.
What is the total amount of storage required to support the performance impact of the encryption?
A.
54 TB
B.
64 TB
C.
72 TB
D.
81 TB
Correct answer is C.72 TB
Exp:- encryption causes 33% performance degradation.
33% of 54TB = 17.82TB
54 + 17.82 = 72TB ( approx)
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54/.66 = 81
81 *.33 = 26.73
81-26.73 = 54.27
D is correct
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Some guy, your comment have not logic.
The performance degradation is 30%.(Avamar TEchnical deployments for service providers pag 27).
The correct answer is b.
(54*0.65)=35.1, there are 18.9 reserved for chk overhead.
35.1 * 1.30 (the 30% of encryption overhead)= 45.63
Answer: 45.63 + 18.9 = 64.53
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What’s 66% of 64.53? I’ll do the math for you.
53.46TB
This is from the design course –
As part of server installation, an Avamar server can optionally be configured to encrypt all backup
data stored on the server. Data encryption occurs on the server. When the server reads the data to
restore it to a client, the data is unencrypted as it is read. This option can only be selected at time
of install and can not be changed. Encryption at rest may incur a server performance penalty
and impact server resources by roughly 33% ‐ drop the “disk read only” limit from 65% to 43% (2/3
* 65%).
The question already assume RAIN and check overhead. To get to 54TB, you need to work backwards from what the total usable amount would be. With you logic, they need 64TB usable, then take a 33% hit before disk read only.
64TB * .66 = 42.24 != 54.
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Should have read what’s 66% of 81?
53.46TB.
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“The original sizing documents indicated that the customer required 54 TB of storage capacity.”
Design Doc: “Encryption at rest may incur a server performance penalty and impact server resources by roughly 33%”
54 x 1.33 = 71.82TB
Therefore “C” is correct
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I agree with Peter. 72TB is the answer.
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