[TriLUG] Linux hard drive questions

[Michael Ham]

Maarten (and others), thanks for the e-mails.  Also, thanks to the guys on
#trilug who spent hours with me Saturday night helping me to figure out how
to use LVM.  

That mhddfs sounds very interesting, but since I've already spent a ton of
time backing up my files, I think I will just use LVM :)  Plus, LVM has been
around a while and is obviously less prone to problems.  Not that I don't
trust this new mhddfs, but if something goes bad.. file systems are not a
good thing to lose.

Hopefully maybe tonight or tomorrow I will be able to begin working on
getting the LVM stuff going.  I've got to use 3 separate hard drives to do
it, but I think I can get it all backed up.

Thanks again,
Michael Ham

On Sun, 17 Aug 2008 Maarten Lippmann <m.w.lippmann at gmail.com> wrote:
Actually there is a relatively new and very easy tool that let's you
'concatenate' multiple partitions into one mount point without any
need to repartition. It works very different from lvm or raid0, and
might be more appropriate for your needs.

It's called mhddfs, and was Debian package of the day some months ago.
For more information see here:
http://debaday.debian.net/2008/05/25/mhddfs-join-several-real-filesystems-to
gether-to-form-a-single-larger-one/

To quote parts of the article:
"<mhddfs> is a FUSE filesystem module which allows to combine several
smaller filesystems into one big ?virtual? one, which will contain all
the files from all its members, and all their free space. Even better,
unlike other similar modules (unionfs?), this one does not limit the
ability to add new files on the combined filesystem and intelligently
manages, where those files will be placed."
"When you create a new file in the virtual filesystem, mhddfs will
look at the free space, which remains on each of the drives. If the
first drive has enough free space, the file will be created on that
first drive. Otherwise, if that drive is low on space (has less than
specified by ?mlimit? option of mhddfs, which defaults to 4 GB), the
second drive will be used instead. If that drive is low on space too,
the third drive will be used. If each drive individually has less than
mlimit free space, the drive with the most free space will be chosen
for new files.
----
if a certain drive runs out of free space in the middle of a write
(suppose, you tried to create a very large file on it), the write
process will not fail; mhddfs will simply transfer the already written
data to another drive (which has more space available) and continue
the write there. All this completely transparently for to the
application which writes the file (it will not even know that anything
happened)."

maarten

On Sat, Aug 16, 2008 at 6:58 PM, Robert Dale <robdale at gmail.com> wrote:
> On Sat, Aug 16, 2008 at 5:43 PM, Michael Ham <michael at bakedhamgames.net>
wrote:
>> Hi Everyone,
>>
>> Sorry, this is going to be short since I was writing a longer, more
detailed
>> e-mail, and of course Windows crashed for no reason while I was doing it.
>>
>> Anyway, the gist of the thing is that I have an old PC running Fedora
Core 5
>> that is pretty much just a file server.  I have a few hard drives on
there
>> that both contain some of my music files. I would like to combine the two
>> partitions into one large partition, even though it is across two hard
>> drives so that I can have it as one large folder for my iTunes library
(yes,
>> I know... it's not Linux... boo).
>>
>> It seems like this may be possible with Linux Volume Groups, but I know
>> nothing about them except that they exist.  Can someone give me some
>> information about how I might go through with this (or if it's even
>> possible)?
>
> You can do this with either LVM or RAID 0,
>
> http://tldp.org/HOWTO/LVM-HOWTO/
>
> http://tldp.org/HOWTO/Software-RAID-HOWTO.html
>
> --
> Robert Dale
> --
> TriLUG mailing list        : http://www.trilug.org/mailman/listinfo/trilug
> TriLUG FAQ  : http://www.trilug.org/wiki/Frequently_Asked_Questions
>



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