[Linux] Combining partitions

[NV]

With unionfs, you are not working at the partition level, its at the 
file system level. Think of it as a more complex way of creating an 
unified tree than using simple symbolic links. Individual files can be 
in different file systems. Or a read-only file could come from one file 
system (say a mounted CDROM) but if you were to write it, it gets copied 
and written to another disk file system. The focus is not on the space 
usage and partitions, but rather how to make it look like one tree.

For LVM, check out ( http://www.tldp.org/HOWTO/LVM-HOWTO/whatislvm.html 
). And your distro's documentation for specific installation instructions.

/NV
--


David Williams wrote:
> Thanks.
>
> I think what I am after is LVM, but now you've got me wondering.  So, with
> this I can add other partitions to the logical partition to increase the
> space on the logical partition ?
>
> Do I then need to always access this via the logical partition name ?
>
> Any good web reading about LVM ?
>
> Regards,
> ____________________________________________
> David Williams
>  
>
> -----Original Message-----
> From: linux-admin@flux.org [mailto:linux-admin@flux.org] On Behalf Of NV
> Sent: Monday, August 18, 2008 3:40 PM
> To: linux@flux.org
> Subject: Re: [Linux] Combining partitions
>
>
> Hi,
>
> I read your question in two separate ways depending on whether I focus 
> on the first part or the later example.
>
> If you are looking for the ability to dynamically reallocate space 
> across "partitions", you can use Logical Volume Management (LVM2 to be 
> precise). The disk(s) are partitioned using LVM tools to create logical 
> volumes which can be dynamically resized at run time.
>
> However, the example you gave suggests a different angle to the problem 
> - how would you create a unified file system, so both /photos and /free 
> look like one file system? If this is what you want, then unionfs is the 
> way to go. Depending on how you configure unionfs, some files will end 
> up in the partition belonging to /photos, others will end up in the 
> partition belonging to /free. Each partition remains distinct and can be 
> accessed independent of unionfs.
>
> One solution works at the disk block level, another at the file system 
> level.
>
> Best,
> NV
> --
>
>
> David Williams wrote:
>   
>> I know that I've heard about this in the past, but don't recall the 
>> exact name. It is possible to combine two separate partitions into one 
>> larger 'virtual' partition right ? So, if I had the following:
>>
>> /photos
>>
>> /free
>>
>> How could I get /free to be an extension of /photos so that the space 
>> from /free becomes available under the /photos partition ?
>>
>> Any help/pointers much appreciated.
>>
>> Regards,
>>
>> ____________________________________________
>>
>> David Williams
>>
>>