| 1: | Why is data redundancy important? |
| A1: | Answer: It provides protection from data loss. |
| 2: | What are three different forms of redundancy? |
| A2: | Answer: Duplicate, parity, and delta (difference) |
| 3: | What's the first step in using delta redundancy? |
| A3: | Answer: Make a complete copy of the data. |
| 4: | List four locations in the I/O path that could contain mirroring operators. |
| A4: | Answer: Host software, HBAs, network systems, and subsystem controllers |
| 5: | Why can't two targets in a mirrored pair have different sizes (capacities)? |
| A5: | Answer: File systems are designed to manage a single address space. This means that all storing (block) operations are duplicated within the boundaries of that address space. |
| 6: | How can mirroring improve system performance? |
| A6: | Answer: Reads can be overlapped, providing parallelism. |
| 7: | Explain how a mirrored pair in a subsystem can be accessed through two different target addresses in a SAN. |
| A7: | Answer: A single logical unit formed by a mirrored pair can be exported by the subsystem through different port/LUNpairs. |
| 8: | Mirroring is sometimes used for remote data protection up to what distance? |
| A8: | Answer: 10 miles |
| 9: | If there are three layers of mirrors working in an I/O path, how many copies of data will be created? |
| A9: | Answer: Eight |