[Techtalk] Faster badblock scans?

[jas at spamcop.net]

Quoting Julie <txjulie at austin.rr.com>:

> Maria Blackmore wrote:
> > On Mon, 25 Aug 2003, Julie wrote:
> >
> >
> >>Does anyone know of a faster way to scan IDE drives for bad blocks?
> >
> >
> > Hi,
> >
> > I'm sorry to say this, but don't bother.  Don't just delete this post as
> > being unhelpful, please read it and take note, it really is for your own
> > good.
> 
> While I appreciate the rant, and could quite easily have written
> it myself, I'd still like an answer to my question.
> 
> For what it's worth, the drives are still in excellent condition,
> with far fewer than 1/100th of 1% of the blocks bad.  Last nights
> scan was of 10,000,000 blocks, of which 9 came up bad.  One bad
> block in 1,000,000 is hardly proof of pending calamity.  Mostly
> the problem is that of the 60,000,000 blocks of IDE drive on this
> machine, 40 or 50 of them seem to have gone bad over the past 12
> to 18 months.

Why aren't they being mapped out by the drive's firmware, though? Is that 
somehow disabled (in which case, just enable it!) - or is that defect list 
already full, at which point the defects you're finding now are just the tip of 
the iceberg - and the disk's dying. (Someone said on another list that IBM 
drives don't do this - if it's an IBM drive, that could also explain the 
problem.)

> And while rants are often fun, in the same sense that a train wreck
> can be fun to watch, the proof that Linux isn't ready for enterprise
> computing is that Linux can't survive having a couple of bad spots
> crop up on a large disk array without barfing.  Seeing as the 240GB
> on this machine is slowly filling, and I expect to have 1TB on it
> before year's end, I'd like to be running an operating system that
> can survive the occasional non-recoverable disk error.

Linux just relies (quite reasonably, IMHO) on the disk's firmware handling that, 
as it's supposed to. Being more tolerant of defective drives would be nice, 
though - and both Windows NT/2k/XP and Linux handle this in the same way: you 
need to be using the fault-tolerant drivers (FTDISK.SYS under NT, software RAID 
under Linux) to get this extra layer of protection. The ordinary drivers just 
assume the drive does what it says on the tin. For 1 Tb of data, there will be 
several drives involved anyway: would adding one more to get RAID 5 be a 
problem? That would avoid the whole issue, it seems: you'd get the extra layer 
of remapping, and you'd be able to recover the lost data instead of just 
identifying it.


James.