Re: Command To Allow Safe Removal of Hard Drive?

Edwin, before I go out and do some homework here to try to explain my
results more precisely, could you point me to a good overview document that
shows how the Windows storage driver stack looks and works?

Thanks for the distinction between volume and disk, and seeing an overview
that helps me clear that terminology would help me make my points clearer.

--
Will

"Edwin vMierlo [MVP]" <EdwinvMierlo@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
message news:%23Q5xR6TdIHA.4588@xxxxxxxxxxxxxxxxxxxxxxx
Right, but we are only using hotswap SCSI and SAS, drives all mounted in
hotswap trays. So electrical disconnect is not the issue. Moreover
the
Symantec commands I mentioned would let you power off a disk device that
is
*not* hotswappable.

No, it just prepares the drivers from Symantec for device removal, this
might or might not be OK for hot-swapping. The Symantec drivers are
upperlayered drivers in the storage IO stack, and not disk device class
drivers, you still need a hot-swap functionality in your class driver.
Symantec are probably a "volume" device drivers, not a "disk" device
drivers.

2) ensure your software (e.g. drivers) supports "hot-swap"

No, I think you are missing the point. Veritas / Symantec
implemented
a
low level

actually there are not that low level at all, depending if you are used
looking at storage stacks, and what angle you approach this stack.

driver that flushes all information to the disk,

only partly true, it flushes to the filesystem and volume, which
ultimately
ends up on a disk, but disk is a different device then a volume device.

prepares it for
power off,

I would like to see that claim being backed up with some documentation
please ?

and then stops the OS from writing anything else to it from the
point that the disk is "detached".

not disk, you mean volume

The very nice thing about that is it
allows you to power off even drives that are NOT hot swappable while the
OS
runs hot.

Nice claim, any documentation about this... now you use the term "drives",
with that do you mean disks or do you mean volumes, as "drives" to me is a
mounted "NTFS volume" represented by a "letter", and to be honest it would
be better not to use the term "drives".

Of course reacquiring a device later that is not designed for
hot reconnection might or might not work and would be hit and miss.
Certainly it works beautifully with SCSI and SAS.


I think you are messing up your teminology big time, and confusing what
the
driver stack looks like.

It could be that you are right, and in that case I am really interested to
see the documentation on that, and will stand corrected.

For now, I am signing off
Rgds,
Edwin.


.

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