OT: redhat

[Bill Campbell]

On Tue, Nov 09, 2004, Fairlight wrote:
>Confusious (Jay Ashworth) say:
>> On Mon, Nov 08, 2004 at 09:43:13AM -0500, Bill Vermillion wrote:
>> > Sure you can add pieces and expand a filesystem anytime you want
>> > >if< you have the right OS. :-) :-) :-) AIX is the only one that
>> > I know of that does that.  :-(
>> 
>> SuSE 9, XFS.
>
>Filesystem is not the question.  PHYSICAL PARTITION (as in...think fdisk,
>folks) is the issue.  I'm talking about needing to join two disparately
>located partitions into one partition and expanding the fs that's on one of
>them to include the space on another.  

The Linux LVM (Logical Volume Manager) or FreeBSD vinum provides this
capability.  There's an interesting feature in thsi month's Linux Journal
on the unionfs which provides some very interesting capabilities joining
multiple file systems types including file system snapshots, software
versioning, and others which I'm not sure I understand yet.

I used LVM on my laptop to join two 2gb physical partitions into a single
4gb partition.  In this case I didn't want to change the physical
partitioning because that would most likely screw up lots of existing
things on the system.

I'm using vinum on our FreeBSD file server here as a concatenated file
system which allows me to add hard drives to a file system.  When I first
set up the file system, I purposely left a hard drive out of the definition
so I could find out how to add a drive.  Basically it was just a matter of
adding the drive to the vinum configuration, then using ``growfs'' to
expande the UFS file system.

>Or are you saying that, given the right fs, you could have it bridge two
>separate physical partitions, and therefore the contiguous nature of them
>is rendered irrelevant?
>
>If you want a real-life example:
>
>   Device Boot    Start       End    Blocks   Id  System
>/dev/hdc1             1      3320  26667868+   c  Win95 FAT32 (LBA)
>/dev/hdc2          3322      3450   1036192+  82  Linux swap
>/dev/hdc3   *      3451      9963  52315672+  83  Linux
>
>The Win95 partition isn't even -needed-.  I'd like to reclaim the space for
>the Linux partition.  I don't see that as possible, as it's non-contiguous.
>And no, I did not do the installation.

You can do this using the LVM, but I wouldn't do it on the ``/'' file
system.  I like to keep the boot partition vanilla so it doesn't depend on
special drivers to boot (another good argument for not having monolithic
single file systems).  This is particularly true with hardware RAID
adapters that require special kernel support.  I like the external RAID
controllers that plug into any standard SCSI host adapter, and look like
one or more large physical drives as these aren't dependent on any special
drivers.

Bill
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