| Steve Morgan on 4 Aug 2006 14:26:29 -0000 |
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I do not believe you need to worry about the speed of the data transfer between internal versus external devices. In my opinion, the transfer of data between the host card and the harddrives should be the same whether they are internally or externally connected. The host card is rated for a certain speed and it delivers it to all connections. It would depend on the type of external box you buy for the disks. Do also take into consideration whether your host card's external interface is Differential or Single-ended SCSI. I have two types of external enclosures in my apartment. One type of box just holds a bunch of disks and conencts them all and dumps them onto the SCSI chain. These harddrives are seen to the host controller as Just a Bunch of Disks (JBOD). The operating system will see each individual harddrive and will work with it as it pleases. This external box connects to the host via Single-ended. The other type of box I have connects to the host via Differential SCSI and does all of the RAID interally, meaning you configure all the drives in whatever configuration(s) you wish on the device itself and the host computer will see those as such. A simple configuration I have setup is all 12 drvies are set up using RAID 0 striping. This presents to the host computer as a single large drive. All of the RAID logic is being done on the external box itself with dedicated hardware, whereas with a JBOD setup all the RAID logic would be software based with the operating system. Depending on how you operate your RAID, whether it is software based with the operating system or hardware based with a dedicated external box or a SCSI controller with RAID capabilities, it will dictate what kind of setup you will end up with. I amdit I am not the best SCSI expert on this list, but if I need to clarify anything for you please feel free to respond on or off list. I invite others to offer their opinions and to correct me on my information should it be wrong. Steve Morgan On 8/4/06, George Gallen <ggallen@slackinc.com> wrote:
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