[plug] Stressing a disk

[Harry McNally]

On 9 Jan 2003 04:14:14 -0000 sscott at iinet.net.au wrote:

> Tis so :D
> 
> It will read ahead and buffer, and also buffer the writes.....
> 
> so instead of /\/\/\/\/\/\/\ (action of head across disk)
> 
> youll get 
>  _________                 ___________
> /         \_______________/
> 
> Modern HDs do all sorts of fancy things to 'go faster'(tm) and 'appear 
> reliable'(tm)...  

Sapristi! Foiled by go faster. Perhaps scattergun writes to random sectors
will keep flushing the drives buffers and force media read write activity.

Multiple backgrounded dd's (>20) might achieve this if they are given different
start offsets.

On some high speed SCSI recording stuff I did a few years ago, we used
SCSI commands to adjust the disk caching to zero to check media I/O.
I've no idea if similar commands are available or IDE; only every used
them as Plug and Go.

On the md5sum, I missed what Tony was doing with that. A dim moment :) 

I'd just be doing thrash-o-rama access on the drives and rely on I/O
error reports at the console. 

cu
Harry

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