Arch Linux

athal

Member

Registered: 2012-05-29

Posts: 16

Partitioning external hard drive

Hey dear community!

I just bought a 500 gb external hard drive and want a partitioning scheme like the following:

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| 150 gb Windows 7 OS |
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| 150 gb Arch Linux OS |
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|200 gb FAT32 USB       |
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That would be no problem, but I want the following features:

Truecrypt encryption of all 3 partitions. Possibility to boot the 2 operaton system (linux and windows) if I
plug in the external harddrive into a computer. So somewhere must sit GRUB...
The 200 gb usb storage partition should also be encryptable by the boot loaded (is that even possible?)

I read the I can just create up to 4 primary partitions. But Linux alone needs 3 partitions:
linux-swap,/boot and /home. So there is no way to use the 4 primary partitions, I need the extended partition. How would you implement my goal? Any resources or hints?

the.ridikulus.rat

Member

From: Indiana, USA

Registered: 2011-10-04

Posts: 765

Re: Partitioning external hard drive

@athal: First check whether it is possible to install and run Windows 7 from an external USB drive. AFAIK you can't.

In that case you can go for GPT partitioning of the drive. Windows Vista/7 will read GPT partitioned USB drives without issues, but you can't access those drives in XP, atleast not without third-party applications.

And if you are planning on encryption of root partition, /boot must be a separate partition and unencrypted.

If you want to use MBR partitioning, there are no issues of linux root partition being a logical one. The requirement of /boot partition being primary depends on the bootloader used. Grub2 works well with /boot logical partition. Syslinux might work with /boot being logical.

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altbdoor

Member

From: KL, Malaysia

Registered: 2012-04-25

Posts: 128

Re: Partitioning external hard drive

hi athal

i do not use encryptions, hence i could not answer the questions related to encryptions.

Possibility to boot the 2 operaton system (linux and windows) if I
plug in the external harddrive into a computer. So somewhere must sit GRUB...

allocate around 100mb or less for /boot for grub to sit in? i mean, with 500gb, 100mb should be nothing
--

I read the I can just create up to 4 primary partitions

yup. that's right.
--

But Linux alone needs 3 partitions:
linux-swap,/boot and /home. So there is no way to use the 4 primary partitions, I need the extended partition.

nope. arch recommends having separate swap, boot, home and root partitions. you can actually fit it all in one partition. however, if you're having multiple distros in the hard drive, a separate boot partition might be a good idea
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How would you implement my goal? Any resources or hints?

first up, install windows 7 (if possible, read below), and let it take the whole drive. then, use gparted, move the win7 partition, such that there is 100mb preceding empty space (that's for /boot). create two new partitions, one for arch, and another for local storage. here's how it will look like

/dev/sda1 = /boot = 100mb
/dev/sda2 = win7
/dev/sda3 = arch
/dev/sda4 = local storage

all this, IF, win7 can be installed. i speak from experience on installing into hard drives, not external drives

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First check whether it is possible to install and run Windows 7 from an external USB drive. AFAIK you can't.

i looked around, and it seems that one could not "really" install win7. most of the people used portable virtualbox or virtualization, like here and here.

Last edited by altbdoor (2012-06-25 12:28:57)

DSpider

Member

From: Romania

Registered: 2009-08-23

Posts: 2,273

Re: Partitioning external hard drive

Ok, let me share some wisdom too. First of all, USB 2.0 is fricken slow! It's only limited to about 20-30 MB/s or so. Not worth it for an OS install, IMO, unless you only use it for mundane stuff like browsing the web, listening to music, etc. And in that case you may as well use SliTaz from a 512 MB stick.

MBR drives are limited to 4 primary partitions, yes. But you can extend one of those and create as many partitions as you'd like. Linux doesn't care where you install it and ever since Windows NT (2000, XP, Vista, etc), you can install Windows to an extended ("logical" partition) as well. Not easily, but it can be done (its boot files still need to be on a primary partition, tho).

The root partition should not be too big. I'd say 10 GB is more than enough. For Windows, Microsoft recommends at least 16 GB.

You don't need a swap partition with 2 GB+ RAM. Except maybe if you plan on using hibernation, in which case you can use a swapfile. Heck, you don't even need a separate /home partition. My system doesn't have one. I like to keep my dot files separate from storage partitions.

PS: Just so you know, FAT32 cannot hold files larger than 4.00 GB. I would go with EXT4 for this one. If you ever need to access it from Windows there's Ext2fsd, which can mount it as Read-Only (which is great in case your Windows install gets a virus).

Last edited by DSpider (2012-06-25 13:15:14)

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athal

Member

Registered: 2012-05-29

Posts: 16

Re: Partitioning external hard drive

Thanks for all your suggestions and help, but it seems that I have a further, more fundamental issue. Since my laptop's screen is fucked up (I broke it after I tried to fix a loose contact), the external plugged in monitor doesn't show anything before the laptop booted and shows the login prompt. So I cannot change the boot source to backup the whole linux system (I heard that dd'ing the whole system in the same running system causes errors, becuase the system is steadily chaning and so the harddisk). I try now to change the boot source in a brute force attempt - which really sucks F2 -> 3 times [Arrow Right] -> [Enter] -> x times [arrow down]

I hate it

Besides:
My external harddrive supports USB3. I'll use it as a backup and storage device. If the Linux OS is bootable and the Windows 7 not, it wouldn't be that bad. I just want the possibility to restore the backed up windows OS easily...