Array failure probably due to corrupted drive

[MurrayFoote]

Thanks very much for that information and links.

At least two of the hard drives have started failing, even by themselves outside a RAID. I'll explore the health of those drives with the links you provided and then may consider whether to buy new ones or use some 2TB WD Reds I have.

[MurrayFoote]

I have a couple of follow-up questions regarding bad sectors.

I used HDDScan to test some of the HGST 3TB drives I previously had in a Drobo. Two had massive numbers of bad sectors and one tested OK. Probably that was the spare not in the Drobo. I haven’t got to the other three of these yet and I guess they are unusable.

I then used HDDScan to test seven 2TB WD Red drives (equivalent to current WD Plus) most of which were in a RAID 10 in my previous PC. They all tested OK with HDD Scan but when I created a RAID 5 with five of them, Acronis hung up on backup tasks. So I deleted the RAID and tested the drives with Disk Genius.

So far Disk Genius has found two of the WD Reds with no bad sectors and three with bad sectors. The one I finished scanning and repaired had 92 bad sectors or 0.04%.

How many (repaired) bad sectors is acceptable, especially for use in a RAID where I cannot continue to check individual disks? Or should I throw away any with bad sectors?

If I get a new HDD and Disk Genius shows bad sectors, should I return it or only if chkdsk shows bad sectors?

[TMRyan]

Hi,

There is no exact data to indicate how many repaired bad blocks can be accepted and used. It depends on your hard drive. A hard drive with many bad blocks may show a lot of bad blocks again after a period of time.

It is recommended that you use a hard disk in good condition or back up the data to another place when using a hard disk with repaired bad blocks.
You can continue to use it in other places to store unimportant data.

After getting a new hard disk, it is recommended that you return it directly and replace it if bad sectors are detected.

If the hard disk has bad sectors, then the data on the hard disk is in danger of losing, so it is necessary to back up in time.