EMC Updated D-ISM-FN-23 Exam Questions and Answers by kareem

An Object Storage Device (OSD) system stores data as objects, each of which includes the data itself, metadata describing the data, and user-defined attributes. This structure allows forefficient data management and retrieval, as objects can be easily indexed and accessed based on their metadata and attributes. This differs from traditional file systems where data is organized hierarchically.References: Dell Information Storage and Management V5 documents, ExamTopics.

To calculate MTTR, we need to convert the hours into minutes. Here are the steps:

• Monday: Port 7 was down from 4 PM to 11 PM. That’s 7 hours or 420 minutes.
• Wednesday: Port 7 was down from 2 PM to 10 PM. That’s 8 hours or 480 minutes.
• Friday: Port 7 was down from 5 AM to11 AM. That’s 6 hours or 360 minutes.
• Total corrective maintenance time = 420 + 480 + 360 = 1260 minutes
• Number of repairs = 3
• MTTR = Total corrective maintenance time / Number of repairs
• MTTR = 1260 / 3 = 420 minutes

Therefore, the MTTR of Port 7 is 420 minutes.

Variable-length segment deduplication identifies duplicate data more efficiently than fixed-length segment deduplication because it can adapt to changes in the data. Even if there are minor differences between two documents, the variable-length approach can still recognize and eliminate duplicate segments. This method increases the probability of identifying duplicate data, improving storage efficiency and reducing the amount of data that needs to be stored.References: Dell Information Storage and Management V5, Data Deduplication Techniques,Dell Certification Resource

RAID 6 uses two parity blocks for data protection, allowing it to withstand the failure of two drives. In a RAID 6 array with four 250 GB disks, the usable capacity is calculated by subtracting the space used for parity. With four disks, two are used for parity, leaving the capacity of two disks for data storage. Therefore, the total usable data storage capacity is 2 * 250 GB = 500 GB.

References:

• Dell EMC Information Storage and Management V5 documentation.
• Dell Certification Overview