Optimising pxeboot disk size

[Paul B. Mahol]

On 12/16/08, Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl> wrote:
>>> it's simple:
>>
>> More simple when you tell it ;-) Thanks a lot, i will try it tonight !
>
> it doesn't have chance - must work :)
>
>>
>>> I wish it's helpful, doing this doesn't just save space but saves time -
>>> you have to upgrade software once.
>>
>> So preserving consistency, which is the most important when you have lot
>> of
>> diskless stations !
>
> exactly. i'm using just NetBSD 1.5 (uses LITTLE memory) + Xserver, so
> there are almost no updates, but anyway - it's stored once.
>
>>> you may like to make /etc-common directory and put most of files there,
>>> and
>>> symlinks in each station's /etc
>>
>> In fact, it makes me think that we miss a concept in mount, or at least i
>> don't know it currently :
>> imagine a -tl (TransparentLayer) option for mount, allowing to mount
>> multiple
>> source to the same directory, for instance /etc :
>
> there is already such think - mount_unionfs
>
> but i don't use it.
>
> if you mount over some directory - it's original contents (like my /etc/rc
> doing exec /systemrc) gets hidden.
>
>>
>> mount -r yournfsserver:/basic/etc /etc
>> mount -tl -r yournfsserver:/TypeX/etc /etc
>> mount -tl -r yournfsserver:/StationY/etc /etc
>
> mount_unionfs
>
> but i don't know how stable it is.
>
>> When you want to change something, you add a rw TransparentLayer :
>> mount -tl yournfsserver:/StationYchanges/etc /etc
>>
>> So that changed or added files are only stored in this rw partition, thus
>> very small and easy to manage.
>>
>> This would be a kind of partition inheritance, like in object languages...
>>
>> Dreams are allowed :-)
>
> try mount_unionfs

and mount_nullfs

-- 
Paul