XServe and SCSI

[Digital Randy]

Hello,

I was wondering if anyone knows whether or not in theory one could replace the Apple supplied ATA drives in an X-Serve with Ultra160 SCSI drives. I know that they are saying that the ATA drives offer nearly the performance of SCSI. But, I have a couple of fairly expensive Ultra160 drives that I’d like to bring with me to a potential X-Serve purchase.

I realize that I could connect the drive to an external port, say the Adaptec 39160, but I don’t want to slow the SCSI bus with the addition of my backup drive, an UltraWide SCSI device. With the limited number of PCI slots this become impossible.

Thanks for whatever light you might be able to shed on this.

 

[gbojim]

Sorry to disappoint you on this but no way.

 

[MacAztec]

gbojim

Why not? I wouldnt know since im not that smart about CPU guts

 

[neilt]

why

simply, Ultra160 and ata are 2 different technologies.
The removable drive sleds in the xserver are made to plug into one of the 4 ata controllers, not scsi controlers.

apple put in the ata in order to cut costs (and my guess is also heat, ata drives don't get nearly as hot as scsi drives) and there is no way to place scsi drives in these hotswap bays.

neilt

 

[tjwett]

Originally posted by gbojim
Sorry to disappoint you on this but no way.

does this mean that the fastest you can go is 7200 RPM? I was considering one for the future but i'd like to get a 10 or 15,000 RPM in there. not possible?

 

[neilt]

Originally posted by tjwett


does this mean that the fastest you can go is 7200 RPM? I was considering one for the future but i'd like to get a 10 or 15,000 RPM in there. not possible?

yep. as of right now that is the fastest ata drive i know of. You can always hook up an external scsi raid via a scsi controller card.

i have been testing one out over the last week, and apple seems to be right on about the performance. I don't have any hard and fast numbers, but i striped the drives together and i max out the network bandwidth (only on 100Mb not gig) while copying data to the striped volume.
I will try to test the gig speeds next week and let you know how it handles that.

neilt

 

[thedude]

scsi

You might be able to run one channel of the Atto or Adaptec card through the internal connector and chain the scsi drives that way. Then use the second one to drive your legacy hardware. But you won't get 4 individual channels or hotplug drives. This does limit you to one external however, and if you've got a medea or something with dual, you would only get 65-75MB/s (i think). If you opt out of the second gigabit ethernet card, you can configure the xserve with a second scsi card, but that seems a little bit of a waste.

Does the legacy drive slow everything down when it's end-of-chain?

good luck!