Re: Hot plugging of SATA disks doesn't seem to work under NetBSD-4.x?

[buhrow%lothlorien.nfbcal.org@localhost (Brian Buhrow)]

        Hello.  Sorry I wasn't clear about scsi disks and hot pluggable
enclosures.  However, perhaps I mis-stated the question.  In relased
versions of NetBSD, at least Versions 2, 3 and 4, given a properly designed
scsi enclosure which permits hot pluggability, the scsitl utility can be
used to good effect to rescan buses after disk changes, and raidframe can
be used to rebuild arrays on swapped drives after drive changes on those
properly designed enclosures, all without bringing a running system down.
        The same cannot be said for SATA disks, which can also be placed in
enclosures which permit hot plugging.  The atactl /dev/atabus0 reset
command does not have the desired effect.
I think this should work, and I wonder how hard it is to make work.
-thanks
-Brian

On Apr 14,  4:23pm, John Nemeth wrote:
} Subject: Re: Hot plugging of SATA disks doesn't seem to work under NetBSD-
} On Sep 4,  8:35am, Brian Buhrow wrote:
} }
} }     Hello.  I have several Sunfire X2200 boxes with SATA disks attached.
} } They probe as follows:
} } 
} } viaide1 port 0: device present, speed: 3.0Gb/s
} } viaide1 port 1: device present, speed: 3.0Gb/s
} } wd0 at atabus1 drive 0: <ST3320620AS>
} } wd0: quirks 2<FORCE_LBA48>
} } wd0: drive supports 16-sector PIO transfers, LBA48 addressing
} } wd0: 298 GB, 620181 cyl, 16 head, 63 sec, 512 bytes/sect x 625142448
} } sectors
} } wd0: 32-bit data port
} } wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
} } wd0(viaide1:0:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using
} } DMA)
} } wd1 at atabus2 drive 0: <ST3320620AS>
} } wd1: quirks 2<FORCE_LBA48>
} } wd1: drive supports 16-sector PIO transfers, LBA48 addressing
} } wd1: 298 GB, 620181 cyl, 16 head, 63 sec, 512 bytes/sect x 625142448
} } sectors
} } wd1: 32-bit data port
} } wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
} } wd1(viaide1:1:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using
} } DMA)
} }             All works well until one of the drives is reset, either because
} } it was pulled out and reinserted, or until it was pulled out and another
} } drive installed.  At that point, timeouts for that drive ensue, and drive
} } resets fail.
} } 
} }     My questions are:
} } 
} } 1.  Are SATA drives supposed to be hot pluggable from a software
} } perspective, as SCSI disks are?
} 
}      In general SCSI disks aren't hot pluggable unless they're hanging
} off a hot pluggable bus such as Cardbus or PCMCIA (or inside a RAID
} enclosure where the RAID controllers deals with drives coming and
} going).
} 
}      Note that in general, hot plugging SCSI devices can do bad
} things.  You should only do it if they are in an enclosure designed for
} hot plugging.
} 
}      SATA drives aren't currently hot pluggable.
} 
} } 2.  If not, has anyone looked at what changes are required to make this
} } functionality work?
} } 
} } 3.  If not, can anyone provide direction on what I should pay attention to
} } if I want to help make that functionality work?
} 
}      Unfortunately, I don't know the answer to these two questions.
} 
} }-- End of excerpt from Brian Buhrow
>-- End of excerpt from John Nemeth