Re: USB Hard Drive

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