Just received inform that our server getting faulty on one in six HD. because we already use RAID 5 the sistem still running normally, but we have to replace immediately, so the sistem can be rebulid and running properly.
RAID (redundant array of independent disks; originally redundant array of inexpensive disks) is a way of storing the same data in different places on multiple hard disks to protect data in the case of a drive failure. However, not all RAID levels provide redundancy.
Effects of a hard drive failure on logical drives
When a drive fails, all logical drives that are in the same array are affected. Each logical drive in an array might be using a different fault-tolerance method, so each logical drive can be affected differently.
- RAID 0 configurations do not tolerate drive failure. If any physical drive in the array fails, all RAID 0 logical drives in the same array also fail.
- RAID 1 and RAID 10 configurations tolerate multiple drive failures if no failed drives are mirrored to one another.
- RAID 5 configurations tolerate one drive failure.
- RAID 50 configurations tolerate one failed drive in each parity group.
- RAID 6 configurations tolerate two failed drives at a given time.
- RAID 60 configurations tolerate two failed drives in each parity group.
- RAID 1 (ADM) and RAID 10 (ADM) configurations
The most common reason for replacing a drive is that it has failed. However, another reason is to gradually increase the storage capacity of the entire system.
NOTE:For systems that support hot-pluggable drives, if user replace a failed drive that belongs to a fault-tolerant configuration while the system power is on, all drive activity in the array pauses for 1 or 2 seconds while the new drive is initializing. When the drive is ready, data recovery to the replacement drive begins automatically.
In fault-tolerant configuration, hot-plug hard drives can be replaced when server is ON, but in case of a Non-hot-plug hard drive, it should be replaced when server is OFF.
For systems that support non-hot-pluggable drives, if user replace a drive belonging to a fault-tolerant configuration while the system power is off, a POST message appears when the system is next powered up. This message prompts user to press the F1 key to start automatic data recovery. If user do not enable automatic data recovery, the logical volume remains in a ready-to-recover condition and the same POST message appears whenever the system is restarted.
Note : in the case I very difficult find some type and model HD, Sowe can replace with different HDD, but the size must be greater from previously,you cannot replace with a smaller size diskAutomatic data recovery (rebuild)
When user replace a drive in an array, the controller uses the fault-tolerance information on the remaining drives in the array to reconstruct the missing data (the data that was originally on the replaced drive) and then write the data to the replacement drive. This process is called automatic data recovery or rebuild with indicator led blinking blue. If fault tolerance is compromised, the controller cannot reconstruct the data, and the data is likely lost permanently.