Re: About to format the whole laptop, need some partitioning advice.
On Mon, Feb 10, 2014 at 11:25 PM, Anubhav Yadav <anubhav1691@gmail.com> wrote:
> [...]
> Windows was very bad again and it created two primary partitions,one 79 GB
> for the windows, and the other 86 mb for bootloader.
Funny thing about that. They're sort of imitating the Linux community
with that, except the Linux community is working to make our version
of the boot loader partition shareable between multiple OSses.
> So tomorrow, I will be installing debian on the remaining space.
>
> Now my question is, What should I choose? Logical volume? or Primary Volume?
The current way of doing things seems to be to have one primary volume
for the Linux boot partition and one logical volume for the remainder
of your partitions. But there are two kinds of logical volumes. One is
what we used to call a DOS (MS-DOS) extended or logical partition. The
other is the LVM you've heard quite a bit about in this thread.
(Actually, you could say there are more kinds than that, including ZFS
and such.)
> I think I cannot create more than 4 primary volumes on a hdd, and
> since two are already
> occupied, I should create
> /home, /, /usr and /var all logical volumes. (Choice of partitions on
> the basis of discussions above)
That's the concept. It is also possible, as has been mentioned, to
install the whole OS in one single partition. Probably. I don't really
think you want to do that, anyway.
> Will choosing logical volumes harm any performance on the hdd?
You're not going to get it right the first time. Or the second time.
And then you will take a different class at school, and what was right
for the last class might not be the best for the next one. That's one
reason you should get an external drive, so you can back your data up
easily and do it a different way, just to see what happens.
Two things you need to understand, you probably don't want to try this
without using some sort of "logical volume". I have had a system where
I had two remaining primary partitions, and I made one swap (1G) and
the other root (the rest of the disk). That was several years ago, and
doing such a thing now is actually harder, not easier, I think.
I think I need to explain those four "primary volumes". I was hoping I
could refer you to wikipedia, but the present article,
http://en.wikipedia.org/wiki/Disk_partitioning
has too much information on stuff that will be distracting from the
purpose here. (Microsfot's page on the topic seems to be just enough
information to help the sales crew, as usual.)
History: Back in the days of MS-DOS, whose evil spawn became the
unworthy standard we now have, in order to keep the disk layout simple
and leave as much as possible for data, DOS fixed the number of hard
disk partitions to four. Because of the elements of the spec that
became the effective standard, we are stuck with that number. These
are what I call primary DOS partitions in my better moments. I'm
pretty sure they are what you are calling primary volumes.
Back in the mid-80s (IIRC), Micorosoff admitted their sins and
grudgingly yielded one of those to be an extendable (or "extended", go
figure) partition. Nowadays it is often called a "logical volume" or
some other term that abuses the English.
(Back then, even among English-speaking computer geeks, there weren't
very many who really understood English. That's why so much of the
jargon is confusing. The situation has not improved, especially since
the sales crew seems to enjoy using the confusion to sell people
things they don't need.)
I'm going to call it the extended partitions. Only one of the four
primary partitions is allowed to be extended, you see.
Within that extended partition, you can cut a number of "logical
partitions". Quite a few, in fact. (I'm going to call them logical
partitions here.) So, what you have looks sort of like this:
DOS (physical) Partition C
DOS (physical) Partition D
DOS (physical) Partition E
DOS extended partition (no letter):
DOS (logical) Partition F
DOS (logical) Partition G
....
The extended partition does not have to be the last one, but there can
be only one.
Now, we don't have to follow this plan in non-DOS OSses. Mac OS did
not, but sort of does now, for compatibility. openBSD and netBSD, and,
I think, freeBSD can take over the whole drive with their own
partitioning system and completely ignore the DOS scheme. But then
it's not compatible with the Microsoft world, and Micorosfot-trained
techs who try to mount such a drive will see no partitions at all, and
think the drive is damaged or blank. And then they wipe the data or do
something else bad.
Linux, likewise, doesn't really have to do it this way. But we try to
maintain compatibility, for dual boot purposes, and to try to avoid
surprising Microsotf-trained techs.
Now, if you use a DOS extended partition, and use DOS logical
partitions, you don't get to re-size the partitions. (At least, if you
do re-size, you could easily lose data.) If you go this way, here's
how it might look:
DOS (primary) partition 1 (MS-Windows boot)
DOS (primary) partition 2 (MS-Windows C:)
DOS (primary) partition 3 (Debian boot, unrecognizable to MSWindows)
DOS (primary) partition 4 (extended, no letter):
DOS (logical) partition (MS-Windos D:)
DOS (logical) partition (Debian root, unrecognizable to MS^Windows)
DOS (logical) partition (Debian something, unrecognizable to MSWinnows)
....
DOS (logical) partition (Debian swap, unrecognizable to
MS-Wingdowns. I'm having problems typing today.)
un-allocated space! (to be later allocated by gparted and mounted,
say, under /home/music2 or such)
The BSDs tend to take a primary DOS (physical) partition and lay their
own partition labels down inside that. It's a little like DOS logical
partitions in a DOS extended partition, except different. So DOS
doesn't count such a partition as an extended partition, and the BSDs
can manage their stuff without worrying about doing things the DOS
way.
LVM is similar. You take a DOS partition and lay down an LVM label
inside it.Then, you cut the LVM partition up into logical volumes.
Last time I did this, my memory was that the LVM partition can now
itself reside in a DOS logical partition, but my memory may be wrong.
I suppose I should check. Anyway, one way it might look is like this:
DOS (primary) partition 1 (MS-Windows boot)
DOS (primary) partition 2 (MS-Windows C:)
DOS (primary) partition 3 (Debian boot, unrecognizable to MS-Windows)
DOS (primary) partition 4 (LVM physical volume, no letter,
unrecognizable to MS-Windows):
LVM logical volume (Debian root, unrecognizable to MS-Windows)
LVM logical volume (Debian something, unrecognizable to MS-Windows)
....
LVM logical volume (Debian swap, unrecognizable to MS-Windows.)
un-allocated space! (to be later allocated by LVM as appropriate)
And the advantage of LVM, as has been mentioned, is that you can take
that un-allocated space and just paste it onto an existing Linux
partition. if /var runs out of space (I've had this happen on a
version upgrade, several times.) all you have to do is use the LVM
tools to grab more of that un-allocated area and add it to the /var
partition.
It's not perfect. It fragments the disk, and you may see some speed
penalty. (I never did, but I didn't see how far I could push it. After
the third or fourth time I added space to /var and /usr, I backed-up
and re-partitioned the entire system.) On the other hand, it can be
used to implement RAID in a sane manner. (Which is definitely not a
speed penalty, if you do it right.) Okay, RAID is not really relevant
to a laptop, at least not for most of us.
You can shrink partitions with LVM, but shrinking is not perfect. So
you would prefer to leave space un-allocated, or maybe allocate it to
something you wouldn't mind just erasing. Like, if you keep a
collection of ripped CDs in your laptop, since you can always re-rip
them, you could just keep them all in one partition and, when you need
space, erase that partition for the space you need.
gparted does NOT work with LVM partitions. There is a graphical LVM
tool. It's a bit simplified and limited and a bit slow to use, but
it's probably plenty good enough to get you started.
> I have also decided to choose xfce as my primary desktop,
> unless I get more knowledgeable in using tiling window managers.
It's a good point to start from. A more bare-bones window manager that
doesn't handle the desktop metaphor for you is an interesting
adventure in itself, but I think you'll want a little more preparation
before you go there.
> Apart from all that I would like to sincerely thank each and everyone of
> you, I never felt that I was alone, always cheered up by you guys.
> No wonder hdd are cheap in some countries say 100-150 $, but here
> in this country, I just could not have afforded an hdd without getting
> some credit from others.
Yeah, for some people the cost of a new HD is a month's wages. For
others, an hour's wages. (But I'm trying very hard not to wander off
into politics here. Did I manage to skip the rant about Microsoft's
monopoly practices above?)
Anyway, it's great you got the HD back up, and are ready for more
adventures. ;-)
> [...]
--
Joel Rees
Be careful where you see conspiracy.
Look first in your own heart.
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