On Monday December 5, mjt@xxxxxxxxxx wrote:
> I found it's quite difficult, after resizing underlying
> partitions, to compute the new size for
> mdadm /dev/mdX -G --size=xyz
> command, because of the way how it finds the superblock
> offset. So, the question is -- is it possible to make
> the argument of --size to be optional, and let mdadm to
> compute the size automatically, just like resize2fs does
> now? Or, maybe, to keep backward compatibility for
> those people who used --size z (as opposed to --size=z),
> to recognize `0' as special size, to mean "whole partition"
> or "max size". The latter is probably the best, i think.
From the man page:
OPTIONS
....
For create or build:
....
-z, --size=
....
This value can be set with --grow for RAID level 1/4/5/6. If the
array was created with a size smaller than the currently active
drives, the extra space can be accessed using --grow. The size
can be given as max which means to choose the largest size that
fits on all current drives.
(The word 'max' is in bold).
So maybe it should be "For create, build, or grow", but it seems to be
there:
mdadm --grow /dev/mdX --size=max
does the trick.
That text in the man page was added for 1.12.0.
>
> The same is for newly appeared --update=uuid:xyz: I'd let
> mdadm to choose an uuid just like it does for newly create
> array, if the uuid argument isn't specified, like:
> --update=uuid:1234 --- use uuid=1234
> --update=uuid --- choose random uid
Again from the man page:
OPTIONS
....
For assemble:
....
-U, --update=
Update the superblock on each device while assembling the array.
The argument given to this flag can be one of sparc2.2, sum-
maries, uuid, resync, byteorder, or super-minor.
....
The uuid option will change the uuid of the array. If a UUID is
given with the "--uuid" option that UUID will be used as a new
UUID and with NOT be used to help identify the devices in the
array. If no "--uuid" is given, a random uuid is chosen.
So I guess it already does what you want.
Any suggestion on how to make the man page clear will be welcome.
Thanks,
NeilBrown
>
> Does it all look ok?
>
> /mjt, who goes to produce some patches...
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