[OpenAFS] vice partition sizes, and large disks

[Bill Zumach]

> Depends on how you set up the raid - if you have them multiple
> partitions on same device it seems that they do not salvage in parallel.
> Although that might be a linux quirk.
> 
> -- Nathan
Transarc found that running more than one salvage in parallel on a disk
on any file system then supported (Linux not supported at time of test) was
slower than running them sequentially. This is because the disk heads were
constantly slewing across the disk to bounce between reading the inodes
for the partitions being salvaged.  Now this may not be the case for raid5. But
I don't off hand see why it would not hold there as well. Since people now
have the source, one could experiment and see if this still holds.

And if this does not hold for multiple partitions partitions on a raid device
then one needs to come up with a scheme to let the salvager know which
devices it can run in parallel on and which it cannot.

Bill Zumach