Just a small question. Does the /r switch have any actual effect when checking a volume that is part of a hardware RAID array? Surely the RAID Controller takes care of bad sector management, and abstracts the physical disks from the operating system?

chkdsk is not RAID aware utiliy its works in simple cases in general it must be avoided if chkdsk tries to repair one or more raid member disk then there is chance that RAID data pattern will be destroyedhttp://www.virmansec.com/blogs/skhairuddin

Ouch! I just ran chkdsk /f /r on my c: drive, and it made corrections to the file system. Have I done bad?

No this is not bad, it found and fixed an issue, but you may want to look for file###.chk files in the root of the drive. These are lost file chains, which may indicate parts of one or more files were lost. The problem is finding those files, and correcting them. Sometime editing these files with a text or hex editor will help determine where they came from. However, in general i have simply deleted the files and never had an issue.

I'm relieved to hear that. What I am getting from all this is that it's ok to run it with the /f switch, but not the /r one. The help for /r says "Locates bad sectors and recovers readable information". It's the "recovers readable information" bit that scares me. In the very old days, there was a DOS utility called Scandisk. It was supposed to be an improvement on chkdsk. In those days, it was ok to have bad sectors on your drive. It was almost expected. The motivation for my original question is that I do not think that the /r switch does anything meaningful, in terms of actually scanning your media for defects, when run on a disk that is part of a RAID array. My reason for thinking this is that the RAID controller abstracts the physical disks, and presents a virtual disk to Windows. So chkdsk has no way of really knowing if a particular cluster on a physical disk is readable or not (which it should be trying to do with the /r switch) Do you see what I mean? What am I missing here?

It seems that opinions are mixed about the desirability of using chkdsk on RAID arrays. Some say yes, some say absolutley no! My opinion is that it is ok, and desirable to run chkdsk /f from time to time on RAID arrays. It is NEVER ok to run chkdsk /r on a RAID array. If you suspect something to be physically wrong with your disks, use the utility that is embedded in your RAID controller. You should verify your RAID arrays using your RAID controller software from time to time. Comments?

Hi, Chkdsk is not a tool for RAID, but sometimes we will need to check disks as you mentioned like physically issue. And it is recommanded to use RAID controller software for RAID disks. This is correct.TechNet Subscriber Support in forum |If you have any feedback on our support, please contact tnmff@microsoft.com.

This subject just came up again in my shop. The front line keeps running chkdsk /f /r on Local raid and SAN drive partitions when NTFS alerts with file system problems. Both types of drives are in a fault tolerant array. Knowing that chkdsk and raid are two different technologies which are totally independent of each other, my feeling is running chkdsk /r is totally unnecessary when youre dealing with RAID partitions. It elongates the chkdsk process exponentially especially when you have extremely large volumes to correct. /f would be the correct switch to use on those types of partitions.