[ubuntu-us-in] hard drive tools* ssh ftp suggestions

[Rob Ludwick]

> I dunno, DD dies with an "Input/Output error" anywhere in those 4096
> bytes. Also, it's incredibly slower at extracting data from any and
> every other sector.

DD is, I believe un buffered reads, but sequentially.  So if it fails on
one sector, it will fail on all sectors.  

Normally in order to get any kind of performance through dd, one would
adjust the bs parameter.  which in this case you can't because the way
you're reading it.

The alternative would be to write some C code that would be able to read
a particular number of sectors, say ~1MB from each disk and the
correlate the data onto another disk somewhere (or say file) that can be
loop back mounted.  At 1MB you get enough throughput from the disk to
make it fairly fast.  And if you get an error, you can just set the
block with a bunch of zeros.

--R