Hi, I just want to make sure how UNRAID works in the following scenario.

Now I am running 6 hdd as single hard drives conected to the sata ports of my MB.

In the following scenario: I am using UNRAID and I have set up an array with my 6hdd + 1parity (all 2TB hdd...and 1 of my 6 disks fail, as happened to me last week... would still UNRAID let me recover all the data from that disk? The disk that failed in my actual setup is not even recognized by windows Disk Mgmnt, neither by DOS using for example Acronis.

I guess UNRAID will not be able too to recover the data in the disk.

So, when I read in LimeTech "Tolerates a single failed hard drive. Array parity permits reconstruction of a single failed data disk." .. what kind of disk failures are not covered?

Rgds.

Hi, I just want to make sure how UNRAID works in the following scenario.

Now I am running 6 hdd as single hard drives conected to the sata ports of my MB.

In the following scenario: I am using UNRAID and I have set up an array with my 6hdd + 1parity (all 2TB hdd...and 1 of my 6 disks fail, as happened to me last week... would still UNRAID let me recover all the data from that disk? The disk that failed in my actual setup is not even recognized by windows Disk Mgmnt, neither by DOS using for example Acronis.

I guess UNRAID will not be able too to recover the data in the disk.

So, when I read in LimeTech "Tolerates a single failed hard drive. Array parity permits reconstruction of a single failed data disk." .. what kind of disk failures are not covered?

Rgds.

unRAID would allow you to recover that one failed disk.  If another were to fail while the one disk was failed you would lose the content on both of those drives but not on the remaining 4.

thx. i also found this usefull link. i guess a catastrophic disk failure will mean in any case the disk is gone.

http://lime-technology.com/forum/index.php?topic=2213

Any single disk failure is recoverable. It doesn't matter if the disk is "recognized" or not since unRAID reconstructs the contents onto a brand new disk without the old one.

 

However, there is a gotcha. You need to have a healthy array before attempting the recovery. If you don't do regular parity checks and have some other "hidden" issue then the rebuild will fail. The pre-existing issues can be things like bad memory or another drive that has had bad sectors (and the bad sectors have corrupted the data on that drive).

 

Peter

 

The disk that failed in my actual setup is not even recognized by windows Disk Mgmnt, neither by DOS using for example Acronis.

 

Windows will read unRAID disks with a Reiser file system driver. This driver is included in most Linux distributions. But as stated, you don't need the failed drive to recover the data on that drive. Parity and the remaining drives are used to reconstruct the data on to a replacement drive. In fact unRAID allows reading and writing to the "failed" drive. You may not even notice it has failed unless you check the management interface or configure unRAID to notify you. Concurrent failure of two drives will likely cause the data stored on only those 2 drives to be lost.