单选题A new Disaster Recovery site has been established using Metro Mirror to hold synchronous data at both sites. After the Metro Mirror is started， one of the most important applications， a DB2 database， slows down. An analysis shows that the I/O rate （esp
题目
单选题
A new Disaster Recovery site has been established using Metro Mirror to hold synchronous data at both sites. After the Metro Mirror is started， one of the most important applications， a DB2 database， slows down. An analysis shows that the I/O rate （especially write I/Os） is less than 40% compared to the former rates. What is the best explanation for this behavior（）
A
the bandwidth of the PPRC connection between the two sites is too small
B
the DS8000 SFI at the remote site was shipped with slower disks
C
I/O rates vary， depending on the distance between the two sites and the rates cannot be changed easily， due to latency
D
the DB2 database does not work with Metro Mirror without an additional license