[CentOS] Re: software raid

[John R Pierce]

> It is the breaking of electrical connections that it trips on. Even if a drive
> fails, it is still commected, and the system can ignore it. AFAIR you can't
> hot swap a regular SCSI drive either.
>
>   


you can hot swap a SCSI drive thats on a SCA (80 pin) connector as that 
connector is specifically designed for it.   IDEALLY, there's a scsi 
backplane processor chip on the SCSI backplane, often SCSI device 15, 
which notifies the host (or raid controller) of the drive changes, but 
thats not absolutely neccessary. 

SCA and SATA connectors intentionally have shorter signal and power, and 
longer ground pins so when they are hotplugged the signals are sequenced 
properly.