What happens when hard disk fails in raid 5
Posted by Vivek Gite
[Last updated: February 16, 2006]
RAID is acronym for Redundant Array of Independent Disks, also known as Redundant Array of Inexpensive Disks. It is use to increase reliability. You combine multiple physical hard disks into groups (arrays) that work as a single logical disk i.e. this array of drives appears to the computer as a single logical storage unit or drive.
RAID-5 features
RAID level 5 has following features:
- Striping with distributed parity
- Fault tolerance supported
- Redundancy supported (parity)
- Hot spare option supported
- Minimum 3 or more disk needed
- Performance: Good
- Protection: Good (if any disk fails data can be recovered)
- Above characteristics makes RAID 5 popular and is well suited to transaction orinted environments.
What happens when hard disk fails in raid 5
- Because of parity, information all data are available in case one of the disks fails. If extra (spare) disks are available, then reconstruction will begin immediately after the device failure.
- However if two hard disks fail at same time, all data are LOST.
- In short RAID 5 can survive one disk failure, but not two or more.
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Related Other Helpful FAQs:
- Howto rebuilding a RAID array after a disk fails
- What are the different RAID levels for Linux / UNIX and Windows Server?
- UNIX / Linux: copy master boot record (MBR)
- Install Linux on Serial ATA (SATA) drives
- RAID for Linux file server for the best READ and WRITE performance
Discussion on This FAQ
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July 11th, 2007 at 8:20 am
i ve 6 disks with raid 5 … Now one of them fails and can i change it directly? Should i have to do anything before replacing the red blinking failed disk ? My server is compaq proliant 1600 ..
July 11th, 2007 at 7:03 pm
If it is hot swappable disk, just replace it. Otherwise shutdown box and replace hard disk. Reconstruction will begin immediately after replacement!
March 12th, 2008 at 11:22 am
Hi,
I had raid 5 with three harddrive of 250 gb… out of three one hard drive fail so according to the raid 5 setup we change the fail harddisk and inserted brand new of 500gb and keep the process for rebuild, it took about 8 hours to rebuild but when the procees was completed i was not able to see the drive in the computer so can you please help to let me know of i am missing some configuration or settings…
cheeers!