Exercises
1. Why is RAID 1 not a substitute for a backup?
2. Why is RAID 0 not an option for data protection and high availability?
RAID 0 is data striping. This means that data will appear to a user as one logical disk but all the data is distributed among two physical disks. If one disk fails operation cannot continue and data is lost because it is only stored in one place.
RAID 1 uses two disks that are mirrored copies of each other. If one disk fails, operation can continue and no data is lost.
3. Explain the process of data recovery in case of a drive failure in RAID 5.
4. What are the benefits of using RAID 3 in a backup application?
5. Discuss the impact of random and sequential I/O in different RAID configurations.
6. A 10K RPM drive is rated to perform 130 IOPS and a 15K RPM drive is rated to perform 180 IOPS for an application. The read/write ratio is 3:1. Compute the RAID-adjusted IOPS for the 10K and 15K drives for RAID 1, RAID 5, and RAID 6.
7. An application has 1,000 heavy users at a peak of 2 IOPS each and 2,000 typical users at a peak of 1 IOPS each, with a read/write ratio of 2:1. It is estimated that the application also experiences an overhead of 20 percent for other workloads. Calculate the IOPS requirement for RAID 1, RAID 3, RAID 5, and RAID 6.
8. For Question 7, compute the number of drives required to support the application in different RAID environments if 10K RPM drives with a rating of 130 IOPS per drive were used.
Chap 5
Exercises
1. DAS provides an economically viable alternative to other storage networking solutions. Justify this statement.
2. How is the priority sequence established in a wide SCSI environment?
3. Why is SCSI performance superior to that of IDE/ATA? Explain the reasons from an architectural perspective.
4. Research blade server architecture and discuss the limitations of DAS for this architecture.
5. What would you consider while choosing serial or parallel data transfer in