On 09/28/2017 11:10 AM, Frank Rust wrote:
> Hi Roland,
> I am not a perl-friend too.
+1
> + my $x=$size;
> + my $unit="gib"; # GiB is default
> + my $factor=1024*1024;
> + if ($x/$factor != int($x/$factor)) {
> + $factor=$factor/1024; $unit="mib";
> + if ($x/$factor != int($x/$factor)) {
> + $factor=$factor/1024; $unit="kib";
> + }
> + };
> + $size=sprintf("%u%s",($x/$factor),$unit);
> + print "Size=$size\n";
> +
> drbdmanage_cmd(['/usr/bin/drbdmanage', 'new-resource', $name], "Could
> not create resource $name");
> drbdmanage_cmd(['/usr/bin/drbdmanage', 'new-volume', $name, $size],
> "Could not create-volume in $name resource");
Apparently, the original size ($size) is in kiB, so the question would
rather be whether it makes much sense to recalculate the size in a
different unit if it is only going to be used for a machine-to-machine
interface.
The most efficient way would be to just pass the original size in kiB to
drbdmanage, because drbdmanage also uses kiB internally, so if a value
in any other unit is passed to drbdmanage, it is recalculated in kiB anyway.
If the size is a number that is not a round number in MiB or GiB, and
you would like to pass in round numbers, I would suggest to just align
the kiB value, e.g.
int alignment = 1 << 20;
if (size % alignment != 0)
{
size = (size / alignment + 1) * alignment;
}
(good luck translating it to Perl ;)
> BTW: I am sure that I never added a VM Image that was not multiple of 1GB in
> size, but other storage implementations seem to have rounding errors causing
> strange sizes after moving images around...
The actual size that is allocated by drbdmanage on the backend storage
will almost never be a multiple of a MiB or GiB, because the size of
volumes is specified as a net value, while the backend storage will have
to be slightly larger to provide space for DRBD meta data.
br,
--
Robert Altnoeder
+43 1 817 82 92 0
[email protected]
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