Storage Status Description

Storage Status	Description
Normal	The mailbox and storage pool support normal read/write operations
Degraded	Some hard disks in the storage pool are damaged or removed, but the storage pool can still read and write normally
Destroyed	Some or all hard disks in the storage pool are damaged or removed, and the storage pool cannot read or write
Syncing	After creating RAID 1, RAID 5, RAID 6, or RAID 10, the status will be "syncing". If the system storage pool needs synchronization, it will be in "preparing" state first; after the system synchronization is completed, the user storage pool will be synchronized. When these RAID types are degraded and a new disk is inserted for repair, the status will be "syncing". Normal read/write operations are possible in this state
Repairing	After the storage pool enters a degraded state, it is in the process of being repaired by selecting disks; or some disks were removed and reinserted, entering repair mode
Rebuilding	The storage pool is being expanded or upgraded in RAID level, and the storage pool enters rebuilding state
Preparing	The system RAID is synchronizing

RAID Storage Modes Explained

1. Basic (Single Disk Mode)

• Principle: Uses a single hard disk to store data, with no redundancy or striping.
• Advantages:
  • Simple and easy to use, no complex configuration required.
  • Low cost, suitable for small-scale storage needs.
• Disadvantages:
  • No redundancy, hard drive failure will lead to data loss.
  • Limited performance, cannot utilize multiple disks for parallel read/write operations.
• Applicable Scenarios: Personal users, small storage needs, or scenarios with low requirements for data security.

2. JBOD (Just a Bunch of Disks)

• Principle: Combines multiple hard disks into a single logical volume, data is stored sequentially, with no redundancy or striping.
• Advantages:
  • Fully utilizes all hard disk capacity.
  • Simple configuration, suitable for expanding storage space.
• Disadvantages:
  • No redundancy, failure of any hard disk will lead to partial data loss.
  • No performance improvement, cannot utilize multiple disks for parallel read/write operations.
• Applicable Scenarios: Scenarios requiring large-capacity storage with no requirements for performance and data redundancy.

3. RAID 0 (Striping)

• Principle: Data is divided into blocks and alternately stored on multiple hard disks.
• Advantages:
  • Significantly improves read/write performance (parallel operations on multiple disks).
  • High storage space utilization (no redundant data).
• Disadvantages:
  • No redundancy, failure of any hard disk will lead to complete data loss.
• Applicable Scenarios: Scenarios with high performance requirements but low data security requirements, such as video editing, temporary caching.

4. RAID 1 (Mirroring)

• Principle: Data is completely copied to multiple hard disks, with each disk storing the same data.
• Advantages:
  • High data security (when one hard disk fails, data can still be recovered from other disks).
  • Improved read performance (can read from multiple disks simultaneously).
• Disadvantages:
  • Low storage space utilization (for example, two hard disks can only use half of the capacity).
  • No improvement in write performance (data needs to be written to multiple disks).
• Applicable Scenarios: Scenarios with high data security requirements, such as financial systems, databases.

5. RAID 5 (Striping with Parity)

• Principle: Data is divided into blocks and stored on multiple hard disks, while also storing parity information (for data recovery).
• Advantages:
  • Balances performance and data security (allows for one hard disk failure).
  • High storage space utilization (only loses the capacity of one disk for parity).
• Disadvantages:
  • Lower write performance (requires parity calculation).
  • Significant performance degradation during data reconstruction.
• Applicable Scenarios: Scenarios with moderate requirements for performance and security, such as file servers, small to medium-sized databases.

6. RAID 6 (Dual Parity Striping)

• Principle: Similar to RAID 5, but uses two sets of parity information, allowing for two simultaneous hard disk failures.
• Advantages:
  • Higher data security (allows for two hard disk failures).
  • Still relatively high storage space utilization (only loses the capacity of two disks for parity).
• Disadvantages:
  • Even lower write performance (requires calculation of two sets of parity).
  • More significant performance degradation during data reconstruction.
• Applicable Scenarios: Scenarios with extremely high data security requirements, such as large databases, critical business systems.

7. RAID 10 (Mirroring + Striping)

• Principle: Combines RAID 1 (mirroring) and RAID 0 (striping), first grouping disks for mirroring, then striping across the groups.
• Advantages:
  • High performance (striping improves read/write speeds).
  • High data security (allows for one hard disk failure in each mirror group).
• Disadvantages:
  • Low storage space utilization (can only use half of the total capacity).
  • Higher cost (requires at least 4 hard disks).
• Applicable Scenarios: Scenarios with extremely high requirements for both performance and data security, such as databases, virtualization platforms.