故障轉移是實現高可用性的極佳方式。它是使用兩套儲存系統(主要和輔助)的工作模式。
輔助儲存系統具備所有主要儲存系統數據的最新拷貝資料,所以可以在主儲存系統發生故障的情況下馬上接管。
故障轉移是通過攔截 I/O 任務使得更換主要儲存系統到輔助儲存系統時能不間斷地保護公司的服務正常運行。
故障轉移必須要主儲存系統將本身的數據持續地傳輸到輔助儲存系統。數據傳輸是通過以水平卷方式複製執行。
數據即時從主儲存系統傳輸到輔助儲存系統創建備份存儲,因此在主儲存系統上的每個變化都會立即反映在輔助主儲存系統上
規劃架構與資料傳輸方式如下圖:
1. 低成本規劃
- Motherboard (e.g. all in one) with 1 CPU- 1 GHz, 1 NIC, SATA 1.5Gbps controller
- 1 GB main memory
- Software RAID
- SATA hard disk drive
2. 一般規劃
- Motherboard with 2 x Dual Core CPU – 2.8 GHz
- 8 GB main memory
- SATA 3Gbps hardware RAID controller with RAID5
- 8 SATA hard disk drives
- 4x 1GbE controller (for bonding)
3. 高階規劃
- Motherboard with 2 x Quad Core CPU – 2.4 GHz
- 32 GB main memory
- SAS/SATA 3Gbps hardware RAID controller with RAID6
- 24 SAS/SATA hard disk drives
- 2x 10 GbE controller (for bonding)
- FC controller
- Enclosure with redundant power supply
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