Re: USB Hard Drive

[DrFranken <midrange@xxxxxxxxxxxx>]

This is a recurring theme: "Why can't my 'high priced' server from IBM 
support commodity component 'x'?" In the past 'x' has been various tape 
drives, 4mm and Travan come to mind, as well as other bits like PATA and 
SATA disk drives. Let me try to shed a little light on why IBM usually 
chooses not to support such devices.

First. IBM Does things that have an actual business case. Oddly enough 
the IBM corporation is in business to make money so when they decide 
what to support on Our system they look at how many people would 
actually make use of such a feature. Then they look at the cost of this 
support and this contributes to a decision to support or not support a 
feature. Remember too that 'support' in the case of IBM i is more than 
just creating a driver for a device - it's long term support of 
configurations and use of the devices. But often this isn't even the 
most important issue.

Second. IBM looks at the device and how it would be useful for Us. How 
would we use it. So lets take a look at how for example a USB drive 
would be used. The common question I've seen, and represented here, are 
as a Backup device. So which drive do you have? I think I have that one 
too, it's a "Cheap one." Yes it works and it has a USB2 interface 
running at 480Mbps. Zing! But wait, that's only 50% more than ONE SCSI 
drive in the system and only 16% of the speed of the current SAS drive 
interface. Beyond that, the drive inside your USB enclosure likely isn't 
anywhere near that fast. So even if it is useful it's a small pipe that 
wouldn't be useful beyond very small systems.

Third. IBM looks at the devices and how will it perform in the IBM i 
environment. They look at things like, oh I don't know, let's pick 
RELIABILITY. In the commodity PC market you can get a pretty good sized 
USB 'box' for cheap money. Is that really where you want the backup of 
your world class server? When it fails, who you gonna call? You're gonna 
call IBM. And all they can say is 'Well we didn't create the device, we 
really can't help you." You of course will argue "But you Support it!" 
and the battle begins. By using your own methods to get data to these 
low end devices you get to use them and IBM gets to say: "YOU 
consciously chose that method of backup to a non-supported device" and 
therefore is off the hook for support. That may sound like a cop-out but 
when the entire system is designed on Industrial Strength, World Class, 
and Rock solid,  there just isn't any great reason to support devices 
such as this that are 'fraught with peril' (my words.)

Another twist is that IBM has to consider how YOU would use it. For 
example others and myself have suggested that carrying around a huge 
stack of CDs full of PTFs is a pain. So we postulated that having all 
those images on a USB 'stick' or drive would be awesome! IBM could say 
"OK we'll support them for that use as it makes sense." But they know 
you'll use them for whatever bright idea you have. So they must consider 
very carefully support if it could be misused and thus create a support 
(and therefore customer satisfaction) nightmare.

So my final words: "Think before you ask." :-)

 - DrFranken

On 2/9/2010 1:05 AM, Jacob Anderson wrote:
> ...but I was hoping that a system
> manufactured in 2007 could mount a USB hard drive and write data to it. My
> cell phone can do that, so why is it that a $22,000 server can't???
>
> That's a jab at IBM. I hope someone from IBM reads this news group. There is
> no reason not to mount a USB hard drive.
>
> -- jake
>