Raid marked as degraded, but hard drive seems ok

tonip · n00b Joined: 07 Jan 2005 Posts: 35

This question is not gentoo-specific, so I hope it's ok to post here ...

I have a 3ware escalade 7006-2 on my gentoo box and a couple of days ago the RAID1 array was suddenly marked as degraded. It couldn't see the second drive (which is only a couple of months old). I took the drive out, put it in a USB case, repartitioned it as one large partition and ran badblocks on it. badblocks ran without any errors and I successfully created an ext3 filesystem on the disk.

Now I don't know whether I should be concerned about the disk's reliability or whether I can just carry on using it. If badblocks didn't come up with anything, does that mean the disk is probably ok? In that case what might have caused the raid to stop seeing it? (there's nothing that's obvious to me in the logs)

Any advice would be appreciated,
Thanks
Toni

fangorn · Veteran Joined: 31 Jul 2004 Posts: 1886

The RAID array degrades also when the Filesystem gets an itch. If the disc produces a timeout (whatever may have caused it), the RAID controller chooses stabilty over performance and marks the disc dirty.

In short, if you depend on the data really bad, replace the disc and use if for less important stuff, else you can try it again. If it happens again it is time to replace the disc.