On 19 Jun 2006 at 21:42, Bart Trojanowski wrote: > I still think you should have varied your drives... especially the ones > in the mirror set. Recall my warning from emails ago about drives with > similar serial numbers, coming of the same production line, having the > same flaws. Hopefully I am wrong. I just heard from a noted developer who has worked on RAID a lot. The rest of this post is more or less his words and from his point of view, not mine (ie. if I say I, assume he is speaking). For SCSI, you are better off having all the drives the same. He has no data on SATA, but the star-topology nature of SATA may not be prone to the same bus-tpology issues that SCSI has. With SCSI, each vendor has a slightly different interpretation of the spec, though usually a legal one. The differences in timing, reconnection policies, etc, by different brands on the same bus can cause hic-ups under very high load. The controller might see a spurious timeout on a device, for example, when the drive is actually OK. For RAID controllers that aggressively defend against problems, this can result in bogus failure reports. With SATA, since each drive essentially is alone on its bus, that might not be an issue. But then again, it might be an issue for the controller chip that has to talk to all of the drives. I don't have much data on that, though. hth. -- Dan Langille : Software Developer looking for work my resume: http://www.freebsddiary.org/dan_langille.php