Section 14.124 Data Redundancy Flashcards
Objective 3.4 Explain the importance of resilience and recovery in security architecture
RAID (Redundant Array of Independent Disks)
Combines multiple physical storage devices into a single logical storage device recognised by the operating system
it’s like turning several smaller storage boxes into one large, organized cabinet in the eyes of your computer! RAID allows the operating system to view the storage as one device
RAID 0
Provides data STRIPING across multiple disks (data striping means splitting data into chunks and spreading those chunks across multiple disks)
■ Improved performance but offers no data redundancy
■ Multiple drives increase read and write speeds (quicker)
■ Suitable for scenarios where performance is essential, and data redundancy is not a concern e.g gaming peformance - latency (everything needs to be fast but you must save progress as drive can fail)
Imagine you have a large file to save. Instead of storing the whole file on one disk, RAID 0 breaks it into smaller parts and writes each part to a different disk. This way, when you need to read the file, all the disks can work together to retrieve the data faster.
It’s like tearing a book into sections and giving a section to each of your friends to read at the same time. You get through the book much quicker than if just one person were reading it. However, remember that RAID 0 focuses on speed and doesn’t provide data redundancy. If one disk fails, all the data in the RAID 0 array is lost.
RAID 1
Provides redundancy by MIRRORING data identically on two storage devices
■ Ensures data integrity and availability
■ Suitable for critical applications and maintains a complete copy of data on both devices
■ Only one storage device can fail without data loss or downtime
RAID 5
Utilises STRIPING WITH PARITY across at least three storage devices
■ Offers fault tolerance by distributing data and parity
■ Can continue operations if one storage device fails
■ Data reconstruction is possible but results in slower access speeds as system needs to analyse the parity information (reconstruct a missing puzzle piece whilst still building the puzzle)
Parity refers to a method of error checking and data recovery. It involves calculating extra information based on the data stored across the disks. This parity information is then stored across the disks along with the actual data. If one disk fails, the missing data can be reconstructed using the parity information from the other disks. It’s like having a backup plan built into the array, ensuring you don’t lose your data even if one drive goes down.
RAID 6
Similar to RAID 5 but includes double parity data. STRIPING WITH DOUBLE PARITY
■ Requires at least four storage devices
■ Can withstand the failure of two storage devices without data loss
Striping with Double Parity: Just like in RAID 5, data is striped across multiple disks to improve performance. However, RAID 6 takes it a step further by storing two sets of parity information. This means if two disks fail at the same time, the data can still be reconstructed using the parity information from the remaining disks.
Think of it like having two spare tires in your car instead of one. If one tire (disk) goes flat, you can replace it and keep driving. If a second tire (another disk) also goes flat, you still have another spare to replace it and continue on your way. This provides extra protection against data loss compared to RAID 5
RAID 10
Combines RAID 1 (mirroring) and RAID 0 (striping). STRIPED ARRAY OF MIRRORED ARRAYS
■ Offers high performance, fault tolerance, and data redundancy
■ Requires an even number of storage devices, with a minimum of four
RAID Resilience Categories
Failure-resistant
Resists hardware malfunctions through redundancy (e.g., RAID 1)
This category refers to systems that can handle and recover from minor issues without significant interruption. In RAID, this typically means being able to continue operating even if one disk fails, like in RAID 1 or RAID 5.
RAID Resilience Categories
Fault-tolerant
Allows continued operation and quick data rebuild in case of failure (e.g.,
RAID 1, RAID 5, RAID 6, RAID 10)
This is a step up, where the system can handle more serious issues without downtime. In the context of RAID, this could refer to RAID 6 or RAID 10, where even if two disks fail, the system can still operate without data loss.
RAID Resilience Categories
Disaster-tolerant
Safeguards against catastrophic events by maintaining data in independent zones (e.g., RAID 1, RAID 10)
○ RAIDs are essential for ensuring data redundancy, availability, and performance in enterprise networks
○ The choice of RAID type depends on specific requirements for performance and fault tolerance
This is the highest level of resilience. It means the system can withstand major disasters, like a fire or flood, without losing data or significant downtime. In RAID terms, this often involves replicating data across different geographic locations.
