So, given that upgrades from windows 2.0 to windows 3.0 were never supported, windows 3.1 to windows 95 didn't work at all, windows 95 to windows 98 mostly didn't work; windows 98 to XP was a fail city and XP to vista was disasterous, why on earth does anyone expect windows vista to windows 7 to have any chance of working?

Seriously, what person in their right mind would even _attempt_ an upgrade?

Sounds like they need a better quality cacheing system, or get some of the pr0n served on a locally hosted CDN. Or stick it on their LAN fileservers. Let's get practical here!

Eircom are not ireland's oldest ISP. They started operations as an ISP in 1996 (or in 1995 as Indigo, which they later bought out) and at the time, there were several other operators in the market: eunet ireland (the oldest commercial), ireland online, heanet (nren), connect ireland and internet eireann.

You are kidding about this, aren't you?

Let me get the facts straight:

- you have "mission critical files", and the network you're transferring them over is so incredibly badly managed that it doesn't support reliable data transfer
- you want a technical workaround for this brokenness.

If this is the case, you don't have a technical problem on your hands; you have a political one.

"Mission critical" has a meaning: it means critical to the success of the operation. I.e. without these files, your operation or someone else's operation will fail.

If your management believes that your files are "mission critical", and you're facing a problem of this sort, you need to document the difficulties you're having, along with measurements to support your claims and then make a clear statement that as long as your network path is completely broken, you are absolving yourself of responsiblility for the correct transmission of these files.

If your management doesn't do anything about this, then the files are not "mission critical".

If you're going to to this, you really need to be very careful about your choice of hardware and software. You need to avoid anything which isn't AHCI 1.3 compliant, as previous versions of the AHCI specification defined only a single FIS register per port, which effectively means that the controller card has to serialise all commands to the port multiplier. So even if you've got a port multiplier with a pile of separate disks, your throughput is going to be trash because the host operating system can only talk to a single disk at any one time. AHCI 1.3 fixes this and allows the host operating system to talk to multiple drives simultaneously.

You also need to be careful in your choice of software driver and operating system. Most of the free unix clones have some form of support for port multipliers these days, but this support is not really optimised towards high performance from sensible hardware yet. NCQ (native command queueing) is really important for performance here. I'll guess that with Windows drivers, you just won't know in advance, because the drivers aren't open source and you just can't tell what's going on inside them.

As previous people mentioned, it's important to configure multiple disks like this in some form of redundant mode. If you have a single volume spread across 5 disks, your risk of failure is going to be 5 times more likely than for a single disk, and the consequences of losing that data is 5 times worse than that of a single disk.