recently, i had the problem that our Dell MD3220 Storage Array was showing Alerts regarding unreadable sectors on disk drives.
Stupidly it didnt say which disk is affected. I thought that this is a old message, which is not cleared.
So my first step was resetting the statistic. If there are really defective sectors, the message will show up again.
The trick is, you cant do this over the gui (Dell MD Storage Manager) – you have to use SMCLI (which is part of the installation of the storage manager).
Here is the command:
scmli.exe your-md-dns-name-or-ip -c "clear allVirtualDisks unreadableSectors;"
The message is gone in my case.
Ps: Here you can find the Command Line Guide for SMCLI: