[Wylug-help] Disk health monitoring

[John Hodrien]

On Thu, 26 May 2011, Simon Greenwood wrote:

> That sounds like a false positive from one of the live CDs. SMART support is
> rather patchy across distributions but Ubuntu certainly has it in Disk
> Utility so try running from that. It could be something as simple as a few
> bad sectors on the disk which would show as a SMART error but shouldn't
> affect performance.

Modern disks remap sectors, but unfortunately not as well as they did on SCSI
as I understand.  I believe SATA only remaps on write, not on read.  There are
SMART attributes that show you how much this has been done.

A read/write badblocks run on an unmounted disk can at least force the drive
to remap these sectors (which if it's an isolated failure, means you can get
back to a state of happiness).  If you're stuck on a failed read, it doesn't
matter how many spare sectors are available, you've just lost data.  So I'd
run a mile from a disk that had a consistently growing remapped sector count,
but I've had disks that have remapped a few, then been fine for years.

jh