The ping-pong effect may happen when storage resources are used in multipathing mode. Which of the following are performance issues caused by the ping-pong effect? (Choose all that apply.)

• A. The LUN access performance deteriorates.
• B. The maximum number of concurrent write I/Os on a block device drops sharply.
• C. Application servers restart automatically and frequently.
• D. I/O timeout is likely to occur on application servers.

Assume a bank customer purchased several OceanStor Dorado 18000 series storage devices and needs to install related hardware. Which of the following statements are true about storage hardware installation? (Choose all that apply.)

• A. Generally, vacant slots in the cabinet must be covered with filler panels to ensure proper ventilation and neat appearance of the cabinet.
• B. When installing adjustable guide rails, the customer usually needs to determine the installation positions. If there is no 1 U scale on the front and rear posts of the cabinet, the customer needs to mark the 1 U scale to facilitate device installation.
• C. Generally, U-shaped supports can be stacked. In this case, a maximum of three U-shaped supports can be used on each side.
• D. After the first power-on and initialization of the storage system, the controller enclosures can only be powered on remotely.

To power on Huawei OceanStor Dorado 6000 storage, a customer must hold down the power button for more than 5 seconds.

• A. TRUE
• B. FALSE

An airport customer has purchased several Huawei OceanStor Pacific scale-out storage devices for service deployment. To ensure service reliability, an engineer has configured the HyperReplication feature on the storage devices and established a remote replication pair between the namespaces of the primary and secondary storage systems. Which of the following statements is true about the running statuses of the remote replication pair?

• A. If the running status of the remote replication pair is "Interrupted", this indicates that an internal I/O error has occurred or the remote replication link is down. As a result, the pair relationship is interrupted.
• B. If the running status of the remote replication pair is "Synchronizing", this indicates that data is being synchronized from the primary namespace to the secondary namespace. In this case, the engineer can enable the protection for secondary resources on the secondary storage system.
• C. If the running status of the remote replication pair is "Split", this indicates that the remote replication link is down or an internal I/O error has occurred. In this case, the pair cannot be synchronized or deleted.
• D. If the running status of the remote replication pair is "To be recovered", this indicates that the internal I/O error of the remote replication pair has been rectified. Data consistency between the primary and secondary storage systems is guaranteed by automatic synchronization.