隨著電氣電子技術的發展，家用電器產品日益普及和電子化，廣播電視、郵電通訊和電腦網路的日益發達，電磁環境日益複雜和惡化，使得電氣電子產品的電磁兼容性(EMC電磁干擾EMI與電磁抗EMS)問題也受到各國政府和生產企業的日益重視。電子、電器產品的電磁兼容性（EMC）是一項非常重要的質量指標，它不僅關係到產品本身的工作可靠性和使用安全性，而且還可能影響到其他設備和系統的正常工作，關係到電磁環境的保護問題。 歐共體政府規定，從1996年1月1起，所有電氣電子產品必須通過EMC認證，加貼CE標誌後才能在歐共體市場上銷售。此舉在世界上引起廣泛影響，各國政府紛紛採取措施，對電氣電子產品的RMC性能實行強制性管理。國際上比較有影響的，例如歐盟89/336/EEC指令（即EMC指令）、美國聯邦法典CFR 47/FCC Rules等都對電磁兼容認證提出了明確的要求。
E20-322 屬於EMC認證中的一門考試
1. A customer is deploying a new Microsoft Exchange environment and has requested assistance with the
associated disk design. They are deploying Exchange for 850 users with an average of 3 I/Os per user.
They expect a 60% read and 40% write distribution.
The customer would like to know the number of disks required for both RAID 5 and RAID 1/0 DMX
configurations with 15k rpm drives. How many disks are required for each configuration type?
A. RAID 5 28 and RAID 1/0 18
B. RAID 5 31 and RAID 1/0 20
C. RAID 5 38 and RAID 1/0 24
D. RAID 5 43 and RAID 1/0 28
Answer: A
2. A customer plans to create two regional offices that are between 800 and 2,000 km away from their
main data center. Each regional office will have a data center that will serve four to six branch offices
between 30 and 50 km away.
At the close of business each evening the customer will shut down the application and transmit changes
to each regional office. The amount of new information sent from the head office each night will vary from
0.5 and 1.5 GB. Later each night, an application at the regional offices will read the data from the head
office and generate approximately 50 MB of new rate information appropriate for its branch offices.
What is the most cost-effective EMC solution?
A. 1. Configure CLARiiON arrays in each office.
2. Use MirrorView/A and T3 networks for all data transfers.
B. 1. Configure Symmetrix arrays in the head office and CLARiiONs in the regional offices.
2. Use OC-3 networks to transmit the same master copy of data from the head office to the regional
offices using Open Replicator.
3. At the regional offices, create a snap of the data received and transmit the changes to the branch
offices using SAN Copy.
C. 1. Configure Symmetrix arrays at all the main data centers and CLARiiONs at the regional and branch
offices.
2. Use OC-3 network links between the main data centers.
3. Use DS-3 between the regional and branch offices.
4. Use SRDF/DM for data transfer in each case.
D. 1. Configure Symmetrix arrays at the head office and regional offices.
2. Configure CLARiiONs at the branch offices.
3. Use SRDF/DM and T1 network links between the head office and regional offices.
4. Use Open Replicator incremental offline push to distribute rate information to the branch offices
using T1 network links.
Answer: D
3. A customer decided to consolidate their storage onto a Symmetrix. They have a mix of Windows and
UNIX servers and want one copy of data for creating backups each night. They also want another copy to
be made during the day. This second copy will be a standby to perform a fast recovery in the event of data
corruption.
The initial survey of the customer environment shows that the read/write ratio of their application is 1. 2
during the day and 5. 1 at night. The application appears to be highly sensitive to disk response times
during the day.
Which initial solution should be considered?
A. TimeFinder/Clones for the standby copy and TimeFinder/Mirror BCVs for backups at night
B. TimeFinder/Snap for the standby copy and TimeFinder/Clone for backups at night
C. TimeFinder/Snap for the standby copy and TimeFinder/Mirror BCVs for backups at night
D. TimeFinder/Mirror BCVs for the standby copy and TimeFinder/Snaps for backups at night
Answer: D