Re: file-backed cgd backup question

[Greg Troxel <gdt%lexort.com@localhost>]

Paul Ripke <stix%stix.id.au@localhost> writes:

>> #!/bin/sh
>> 
>> dd if=/dev/zero of=VND bs=1m count=1
>> cat VND > VND.000
>> vnconfig vnd0 VND
>> cat VND > VND.001
>> newfs /dev/rvnd0a
>> cat VND > VND.002
>> vnconfig -u vnd0
>> cat VND > VND.003
>
> At least this DTRT:
>
> dd if=VND of=VND.004 iflag=direct

That (and thanks for the AIX note) is interesting, but I don't see that
it makes backup programs work right.

It seems that the current man page caution about consistency is correct,
and that it would be great if someone added a cache invalidate on close.
(It's a little scary to touch this code in terms of how much it could
mess people up.)