Dual or single channel SCSI RAID?

[Tekunda]

I am trying to build a SCSI Raid 0 system but I admit I am confused with the dual vs. single channel issue.
To get maximum speed for Raid 0 would I need to go dual channel and does this mean 4 hard drives instead of 2 for a Raid 0 array?

Please help me here to understand.


BTW, I wanted to go with SAS drives, but the Seagate 15k.5 drives are extremely expensive, so I think I will go with Maxtor Atlas II 15.5k drives.

Any thoughts on this?

 

[blakerwry]

Dual vs single channel refers to the data interface between your RAID controller and hard drives.

In a U160/320 SCSI setup, multiple drives can be chained off a single cable. Each cable represents one channel. Since the media is shared, only one device can talk at a time. By breaking up devices onto multiple channels you can increase (potential) bandwidth and provide some additional redundancy.

In SAS/S-ATA, this is all irrelevant because each drive has a dedicated data pipe to the controller.

With that said, in a U320 2 drive RAID 0 setup you will not likely saturate the bandwidth of the data interface. So a single channel is sufficient. Where multiple channels become important is in larger arrays or arrays where redundancy is more critical.

 

[sechs]

With your questions answered, may be you could tell why on earth you want to use a RAID 0 array.

 

[Mercutio]

I use RAID0 in preference to JBOD arrays when all I want is a larger-than-a-single-drive volume.

But then I also mirror everything.