DEE-1111 Exam Dumps - Expert - PowerMax and VMAX All Flash Solutions

A noisy neighbor issue occurs when one or more applications consume more resources than expected, causing performance degradation for other applications. This can affect the SL compliance of a storage group, as the service level defines the expected response time and performance for the applications in that group. If a noisy neighbor consumes too much cache, bandwidth, or CPU cycles, it can cause the SL compliance to drop below the target level. Therefore, answer A is correct.

B, C, and D are incorrect because they are not likely to cause SL compliance impact for a storage group. Queue depth full event (B) is a host-side issue that occurs when the host queue depth is too low or the host I/O rate is too high, causing the host to stop sending I/O requests to the array. Host queue depth setting © is also a host-side parameter that determines how many I/O requests can be queued by the host. Performance thresholds (D) are user-defined values that trigger alerts when certain metrics exceed or fall below the specified levels. None of these factors affect the SL compliance of a storage group on the array.

In an SRDF/Metro Smart DR configuration, the Fault-Aware Witness gives a higher priority to Bias when selecting the winning array. The bias settings for the devices are used to determine the preferred winner in the event of a failure2. The preferred winner is the side that has priority when requesting the lock from the witness instance2. References: Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices

The symauth command is used to manage user authorization for SYMCLI commands. The exhibit shows the output of the symauth -list command, which displays the user groups and access types defined for SYMCLI commands. The output shows that there are two user groups: AdminGrp and EmcMgmtGrp. The AdminGrp group has ADMINRD access type, which means that users in this group can run any SYMCLI command with read-only access. The EmcMgmtGrp group has BASECONTROL access type, which means that users in this group can run only a subset of SYMCLI commands with read/write access. Therefore, the correct description of a possible configuration created by SYMACL is hosts that are part of AdminGrp group2

the maximum number of SCM RAID groups that can be added to a two-engine PowerMax 2000 would depend on various factors including the specific configuration of the system and the capacity requirements.

In a Concurrent SRDF/Star configuration failure, the first step to recover is to switch to the 1st Target Site. This is because in a Concurrent SRDF/Star configuration, there are two target sites and one source site. If there’s a failure, the source site can switch to either of the target sites based on the business continuity plan1. References: Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide

The -precopy option in the relink command can be used when you want to start copying data to the target devices immediately after the link operation. This can be useful in situations where additional volumes have been added, increasing the link to full copy time. By using -precopy, you ensure that the data starts copying immediately, preventing potential issues.

The metrics that are recommended to start analyzing the overall efficiency of the array due to cache are array-level % Hit and % Cache WP. The array-level % Hit metric shows the percentage of read requests that are satisfied from the cache memory, without accessing the physical disks. A high % Hit value indicates that the cache is effective in reducing the read latency and improving the performance. The % Cache WP metric shows the percentage of cache memory that is occupied by write pending data, which is data that has been written to the cache but not yet destaged to the physical disks. A high % Cache WP value indicates that the cache is under pressure and may not have enough space to accommodate new write requests, which can lead to performance degradation. By monitoring these two metrics, a storage administrator can evaluate the overall efficiency of the array due to cache and identify any potential issues or bottlenecks.

References:

• System efficiency overview | Dell PowerMax: Data Reduction | Dell Technologies Info Hub
• Metrics (PowerMax & VMAX) - VMware Docs
• Dell EMC PowerMax storage
• Replication cache | Dell EMC PowerMax and VMAX All Flash: TimeFinder SnapVX Local Replication

 In an SRDF/Metro configuration with bias setting, if there is a failure at the R1 array (which is configured as the bias side), the R2 device automatically becomes the active device. This means that even if there’s a failure on the R1 side, operations can continue on the R2 side without interruption, ensuring high availability.

https://infohub.delltechnologies.com/l/dell-emc-powermax-and-vmax-all-flash-srdf-metro-overview-and-best-practices-1/understanding-bias