Volume Manager software for Linux
JP
(??) veritas based like SUN and Sequents (IBM) offerings that can run on
Linux 2.2.x / 2.4.x
JP
Peter T. Breuer
linux's LVM.
What is LVM good for? I've never seen the advantage over linear raid, in
practical terms. I suppose a virtual disk is a nice idea, though. But you
can do it other ways: via loopback for examble.
Peter
JP
Peter T. Breuer <p...@oboe.it.uc3m.es> wrote in message
news:62dp49...@news.it.uc3m.es...
> What is LVM good for? I've never seen the advantage over linear raid, in
practical terms.
I suppose this gets down to what youre used to. I've used hardware raid (a
little) before and whilst it was possibly more robust when
mirroring/striping felt it was a little inflexible in some instances.
Using a volume manager to create disk volumes on the fly, increase/decrease
disk (partition) sizes always seems a lot easier that normal partitioning of
a disk or in the case of linux using fdisk and not having enough disk space
left.
> I suppose a virtual disk is a nice idea, though. But you
> can do it other ways: via loopback for examble.
What is loopback? I've only heard of that regards networking...
JP
Peter T. Breuer
> What is loopback? I've only heard of that regards networking...
You can mount any file as a partition, using the loopback device (man
losetup).
Peter
JP
> You can mount any file as a partition, using the loopback device (man
> losetup).
Cheers, I didn't know about that...
Sounds like it could have performance problems and you'll still be limited
to the actual size of the partition or does this allow spanning of disks?
JP
Markus Kossmann
kernel.
--
Markus Kossmann
markus....@inka.de
José Luis Domingo López
Hash: SHA1
El día Thu, 25 Jan 2001 15:26:14 +0100,
Peter T. Breuer <p...@oboe.it.uc3m.es> escribió:
LVM (Logical Volume Management) doesn't try to be the same as RAID, though
there are some RAID setups that can be "emulated" throught LVM. LVM lets
you have a huge (or not so huge) pool of hardware storage devices (aka hard
discs), and use available space in a very flexible manner. For example,
you can combine all those devices (Phisical Volumes) into a bigger unit
called Volume Group. From a given VG you can create what it is called
Logical Volumes, similar in concept to the partition concept we are all
used to, and create a filesystem over it.
At first sight this could appear as too complex and not very useful, but
what makes LVM valuable is the ability to resize VG and LV on the fly,
with no data loss, apart from being able to make "snapshots" of your
volumes to restore a previous state. Resize means adding and removing
space to/from a given LV or VG, and even add new hard discs to a Volume
Group without problems. No more destructive repartitioning, no more
backing up all your data and then copying it to a larger disk: just
install the new hard disk, add it to the desired VG, and give the LV where
the filesystem is running out of space more megabytes from the VG pool.
LVM lets you combine several hard disks into a larger data pool, where you
can get megabytes and assign them to "partitions", where you have
filesystems. There are options to make a LV take space from various
physical devices at the same time (striping). RAID linear mode is standard
on LVM, because you can "append" partitions one along each other.
- --
José Luis Domingo López
Linux Registered User #189436 Debian GNU/Linux Potato (P166 64 MB RAM)
jdomingo EN internautas PUNTO org => ¿ Spam ? Atente a las consecuencias
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JP
news:3A706A02...@inka.de...
Thanks Markus, thats just what I was after.
It looks very much like LVM on HP-UX, definately worth looking at.
JP