Exam CISSP topic 1 question 120 discussion

I think the keyword is BEST. Yes RAID 1 provides fault tolerance and redundancy, but is it BEST? With RAID 1, fault tolerance is good since more than one disk contains the same data. However, in the case of a write operation, both the disks can get corrupted which will eventually result in a data loss. RAID 5 offers fault tolerance like RAID 1, but instead of using mirroring, it uses parity and checksum where the data is striped and stored evenly across all disks, along with their parity, so the data can be reconstructed at any time.

I go with A Raid 1 provides redundancy and fault tolerance while Raid 5 provide fault tolerance but not redundancy

RAID 1 offers superior redundancy because it maintains an exact copy of all data on a second drive. In contrast, RAID 5 uses parity to protect data, which is efficient but slightly less strong in terms of redundancy.

https://phoenixnap.com/kb/raid-levels-and-types It is A. The corrupt sector argumentation is not correct -> if a sector is corrupt the mdadm program is going to use the non-faulty sector of the other device. THIS is the reason why we want RAID-1

RAID1 for FT and redundancy

RAID 1 (Mirroring): Redundancy: 100% (Complete duplication of data on each disk) RAID 3: Redundancy: 33.33% (Dedicated parity disk can reconstruct data in case of a single disk failure) RAID 4: Redundancy: 33.33% (Dedicated parity disk can reconstruct data in case of a single disk failure) RAID 5: Redundancy: 33.33% (Distributed parity across all disks can reconstruct data in case of a single disk failure)

A. RAID level 1. If you prioritize the highest level of fault tolerance and minimal downtime, RAID 1 is often considered the best choice. If you need a balance between fault tolerance and performance, and you can accept a brief period of vulnerability during disk rebuilds, RAID 5 might be a suitable choice.

D. RAID level 5 RAID (Redundant Array of Independent Disks) is a technology that combines multiple physical disks into a single logical unit to improve performance, reliability, or both. Each RAID level offers different features and trade-offs in terms of redundancy, fault tolerance, capacity, and performance. additional raids, 6, 10 and 50,

RAID5 is the answer: "RAID 0 lacks data redundancy, ergo, it is not a fault-tolerant array." "write speeds of RAID 5 suffer due to the redundant creation " https://www.trentonsystems.com/blog/raid-levels-0-1-5-6-10-raid-types

A The next-simplest RAID level uses mirroring. This takes all data written to one drive and writes it in parallel to a second drive. This provides the highest redundancy since there is a 1-for-1 copy of all data written. https://deft.com/blog/the-levels-of-raid/#:~:text=Disaster%20Recovery%20%26%20AWS-,RAID%2D1,copy%20of%20all%20data%20written.

RAID level 5 provides the best redundancy and fault tolerance out of the given options. It uses distributed parity to achieve data redundancy and is able to sustain a single disk failure without losing data. RAID 1 provides mirroring but only allows for a single disk failure, while RAID 3 and 4 are not commonly used in modern systems.

Best redundancy and faulty tolerance is RAID 5

RAID level 5 uses data striping with distributed parity, which means that data is written across multiple disks in a striped pattern and parity information is distributed across all the disks in the array. This allows for a single disk failure without data loss and allows for recovery from multiple disk failures. It also provides good read performance for small-block random I/O and moderate write performance. - source: openai

RAID level 1 (mirroring) volume layout offers the following: Groups two or more disks as one virtual disk with the capacity of a single disk. Data is replicated on each disk, providing data redundancy. When a disk fails, the virtual disk still works. The data is read from the surviving disk(s) RAID 3 is a RAID configuration that uses a parity disk to store the information generated by a RAID controller instead of striping it with the data. Because the parity information is on a separate disk, RAID 3 does not perform well when tasked with numerous small data requests. RAID 4 is a RAID configuration that uses a dedicated parity disk and block-level striping across multiple disks. Because data is striped in RAID 4, the records can be read from any disk. However, since all the writes must go to the dedicated parity disk, this causes a performance bottleneck for all write operations. RAID 5 is a redundant array of independent disks configuration that uses disk striping with parity. Because data and parity are striped evenly across all of the disks, no single disk is a bottleneck. Striping also allows users to reconstruct data in case of a disk failure.

The difference between RAID 3 vs RAID 5 can be summarized as follows: Mirroring, redundancy and fault tolerance are the main components of RAID 3. RAID 5 cannot boast of this, with fault tolerance storing parity information in one of the drives of the array.

Best answer is A - RAID 1 Disadvantages of RAID 5: Drive failures have an effect on throughput, although this is still acceptable. This is complex technology. If one of the disks in an array using disks fails and is replaced, restoring the data (the rebuild time) may take a day or longer, depending on the load on the array and the speed of the controller. If another disk goes bad during that time, data are lost forever.

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