The air has to pass over more hot components between intake and outlet (shorter to go front to back), meaning that either the components at the top of the rack get to run stinking hot or you push the air through very quickly, thus using a lot of fan power. On the upside this does suggest a reasonably good delta T across the chassis providing some opportunities for efficiency in the cooling plant if you are in a brand new data centre.

Of course there is no reason not to buy this stuff in place of any of the 'major' vendors tin. Each blade chassis design is out of date and needs replacement by the time you can buy it, they are all completely proprietary to ensure high margin, thus appalling value for money and none of them play nicely within your existing data centre anyway. You may as well buy Verari or Egenera, at least these guys have done a little more than taking the case off 10 of their 1U servers and then charging you a fortune for the case, erm, cough, blade chassis, you need for all those 1U servers without cases or power supplies....

...if they didn't keep screwing up pit stops with that infernal electric lollipop!

Wait a minute...

Comparing Hp/IBM/Verari with Egenera BladeFrame is a bit like comparing the management system on a bicycle, with the management systems on an F1 car...... (to keep David W.s errr rrr.....analogy going).

BladeFrame is not about density/packaging/cooling, although it has some benefis in this area, as HP keep telling us, Its about management and deployment, which PAN is all about!

"....Each blade chassis design is out of date and needs replacement by the time you can buy it...." We still have some old HP p-class blades and some IBM HS20s in use, both over four years old and not retired yet. We will probably replace them with c-class at some point, but for now they do the job just fine.

"...they are all completely proprietary to ensure high margin...." Really? I thought it was so they could perfrom better in a more compact package with better power savings compared to rack servers. At least, that's what we see. If that saves us more money in the long run then I'm not to bothered if the vendor makes a smidge more margin.

"...thus appalling value for money...." Our saving point used to be around five blades in a chassis, at which the total cost (purchase, support, operational) became less than five racked servers. Currently, the saving point is at around four blades - if a "green-field" project requires more than four dual-socket servers then it's cheaper for us to go blades. Maybe you need to have a chat with your reseller about how much he's skinning you for!

"...and none of them play nicely within your existing data centre anyway...." What, they don't share they're sweets with the other servers? They interconnect via exactly the same cable types as racked servers, they use the same protocols, and they're easier to manage. In the case of HP, IBM, FSC and Dell, they use expanded sets of the same management tools that racked servers use, something Egenera definately can't claim, as PAN is for their frames only.

"....You may as well buy Verari or Egenera, at least these guys have done a little more than taking the case off 10 of their 1U servers...." I haven't any experience of the Verari kit so I'll take your word for it, but for the Egenera kit they certainly did more - they had to make a specially cut CD for each rack to boot off (not customer cutable), PAN couldn't manage more than one rack at a time, and they had storage bottlenecks through the virtualised fibre channel blocks because they spec'd two 2Gb FC cables for the whole rack. Egenera, though fascinating technology, just didn't meet our requirements, and that was before we started to look at branch offices where we needed just a small chassis to replace usually less than six racked servers. Given also that IBM and HP (and even Sun) could also put UNIX blades into the same chassis as x64 blades, allowing us to consolidate old UNIX apps onto new kit with much lower operational costs, and you may get an inkling as to why I smile at your post.

/still looking for pointing-and-laughing icon!

"Egenera definately can't claim, as PAN is for their frames only" errrrrr........ wrong!

FSC have ported PAN to their Blades, Dell have announced the same intention albeit on the rack servers.

There are a number of instances of high-performance/throughput apps running on PAN, as for 2 FC cables per rack I think you'll find you can get more in a Frame now