fixing a bad sector

[steve%prd.co.uk@localhost (Steve Blinkhorn)]

I have discovered a problem on a live server (i386) I run - this 
is filling up /var/log/messages so that it has turned over more than
10 times today.

The message:

Sep  5 16:56:49 trafalgar /netbsd: wd0a: error reading fsbn 1005056 of 1005056-1005087 (wd0 bn 1005119; cn 997 tn 2 sn 17), retrying
Sep  5 16:56:49 trafalgar /netbsd: wd0: (uncorrectable data error)

The fsbn is mostly 1005056 but sometimes 1005086.

Server response time is impacted.

I've never had, so never tackled, this kind of issue before.   Advice
much appreciated.

-- 
Steve Blinkhorn <steve%prd.co.uk@localhost>