Hi, I have a ReadyNAS NVX with 4 drives: Ch1 1.5TB, Ch2 1TB, Ch3 1.5TB, Ch4 1TB. It is set up in X-RAID2. The drive in Ch4 just failed and I replaced it with a 3TB WD RED drive. When I put the new drive in to resync it starts fine. About 3/4 of the way in the drive in Ch2 fails and completely disappears. This drive is giving more ATA errors and SMART errors. I have a new drive for Ch2 ready (another 3TB WD RED drive) but I need Ch4 to resync before I can swap it out. If drive 2 is toast can I rebuild everything with new drives in Ch2 and Ch4? I'm not sure what I can do. If I pull drives 1 and 3 can I have the NAS copy the failing Ch2 drive to a new drive? All help is appreciated. No one expects to have a dual drive failure.
I'm guessing from what you've said you have no backup?
Whilst we all hope that we won't encounter dual disk failures it is one reason why backups are important. Dual disk failures are not impossible. When a disk fails and you replace it, all the disks are put under heavy stress by the resulting resync. The new disk has to be synced sector by sector with the other disks to be added to the RAID.
X-RAID2 single-redundancy can withstand one disk failure not two.
You may wish to consider contacting support and purchasing an initial diagnostics data recovery contract. Note that a data recovery attempt may be unsuccessful in which case you would need to restore your data from backup (if you have one).
You could try cloning disk 2 using dd_rescue:
readysecure1985 wrote:
Here is a simple guide to quickly recover a failed drive using dd_rescue.
I often have to deal with pesky failed drives, so here is a quick simple guide how to achieve this with a free Linux Live CD and a PC with two SATA connections. I will be using a Knoppix 6.2 Live CD for this guide. Can be found at http://www.knoppix.net Using dd_rescue command allows you to copy data from one drive to another block for block. This is especially useful for recovering a failed drive. Often when a drive fails, the drive is still accessible, it has just surpassed the S.M.A.R.T. error threshold. dd_rescue allows you to ignore the bad sectors and continue cloning the bad drive to a new healthy drive.
1) Connect your old drive and new drive to your PC 2) Boot up using your Linux live CD 3) Launch a terminal window. 4) Run fdisk -l to make sure the system sees both of the hard drives. 5) Run hdparm -i /dev/sdx on both of the drives to find which drive is your source drive and which drive is your destination drive 6) Once you know which drive is which you can start the clone process.
dd_rescue /dev/sdx(source disk) /dev/sdx(destination drive) 7) You will see the process start, just keep an eye on it, it might take a few hours for the clone job to finish, depending on the size of the drive.
Once the process is complete, there will be no notification, the transfer will just stop and you will see the terminal prompt again.
If you see a lot of errors or see that there is no more data being shown as succxfer: it means the drive got marked faulty by the kernel. At this point reboot the system and make sure you know which drive is which again, as it is possible they lettering might switch. Run the dd-rescue command again but this time with -r option. This will start the cloning again but this time will start from the back of the drive and will make sure to get the data that has not been cloned yet.
So what I'm doing currently is backing up the data on the NAS to the drive I was going to use to replace Ch2. If that's successful I'll just pull the bad drive in Ch2 and reformat the X-RAID2 using 3 drives. When that Is done I'll transfer my backup to the NAS and either add a new drive to make it a 4 drive NAS or add the drive I'd used as a backup. I now see that I'll need a backup drive though, regardless.
