Can drives with different speeds be used on same RAID controller?

Hi,

This is a matter of great debate. We do not recommend mixing rotational speeds or Scsi speeds in the same array. I emailed the technical support for IBM, Seagate and Maxtor asking the same question and got 3 different answers. However "technically" the newer faster drivers are supposed to be compatible, slowing to the speed of the slowest component on the Scsi chain.

The answer is YES, but you really don't want to do this unless you have no choice.  Maybe a temp install until you get a similar speed drive or upgrade the others to faster ones to match.

It will work, but if your system syncronizes the Index signal on the drives it will cause problems as the faster drive will never syncronize with the slower machines and may cause slower data retrieval.

I worked for Seagate in the Engineering lab for 3 years before I moved on to something else.  I tested the SCSI drives in development and one test was Index syncronization.  (ensures spin rate is equal on all drives for faster data transfer in a RAID since data is spread over all drives sequentially.)  To put it in common street language, This way data can be retrieved in larger chunks at once from accross all drives at once as all are at the same point in rotation when the data is requested.  The Index signal is what marks the rotation of the disk, 1 rotation per Index mark.