Hi, Linux newb, here. I hope this is the right section of the forum (my newbness outweighs any other considerations, I assure you).

Some background: I'm primarily a Mac user, but I've always been curious about Linux. My second laptop (Windows) is dying, and instead of replacing it, I'm upgrading my Mac for a dual boot. Enter Linux. (I still need Windows for software that is expensive to replace, but I'm tired of the perpetual software/hardware end-of-life issues. Due to the nature of this software, I may never be completely without a Windows device.) To accomodate this, I'm installing a 500gb SSD as primary, and a secondary 1 TB 7200 drive. (It is an older but still very functional Macbook Pro with its max allotment of 8gbs RAM).

The method I plan to follow will be similar to that outlined in this 2010 Lifehacker article, using rEFIt, now reFINd, and skipping Bootcamp. Hopefully not too dated. The new SSD will be formatted and partitioned from original Snow Leopard disk, then upgraded online, and the second drive installed. After that, the two later installations will be from an external USB drive.

To complicate it further, I'm going to use Parallels to virtualize the Win 7 partition, which will mostly be used for AUTOcad and Photoshop. It's primarly 2D stuff, anything heavier, and I will boot into it. (I use ACAD on a supremely underpowered laptop now, so this is a huge upgrade.)

1) One thought, since I will already be using Parallels, is to virtualize Linux from the 2nd drive. Can the Linux swap be located entirely on the second drive, and what about the boot partition? I'm considering a small swap partition/file on the SSD (maybe 2-4gb) to take advantage of the speed, and a larger 8gb swap partition on the second to allow hibernation. Can swap files and partitions coexist (swap file on SSD, secondary larger swap partition on secondary drive), or must they be of the same species, i.e. two partitions?

2) Which configuration would make it easiest to change distros, and delete/resize partition?

3) How much space do I need? (Elementary OS says 15gb, but is taking up 1gb on a thumb drive. It could be faster.)

4) Recommended file sharing methods? I want the OSes to see/read each other at minimum, but will probably forgo writing to one operating system's home folder for stability sake. At this point I'm leaning towards an exFat partition on the second drive for sharing without /home status. (The downside: I can imagine this getting messy with lots of duplicated files.)

5) Which order must each OS go on the boot drive partitions? Lifehacker says 1. Mac 2. Windows 3. Linux 4. Linux swap, yet I heard conflicting information about which OS wants to be where.

6) Is a 500gb drive adequate for three OSes?

I have Elementary OS on a thumb drive, and while I like it, it's not fully ready. Granted, it's beta. I downloaded the 32 bit for my older laptop, and the last supported 32-bit version was Freya. Others I want to try are Manjaro, Ubuntu, and Mint.

Any insight will be greatly appreciated, and congrats if you simply got this far!

Try to ignore any 32 bit distros - it isn't always supported & the 64 bit is always available.

Linux can happily run with swap on one or more disks or no swap at all.
4GB should be ample.

I think you will find that Mint has the most Windows-like appearance.
You could easily fit it into 50GB (unless you have very large data files).

Install Linux last, because when Windows is installed it can screw up your booting mechanism.

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What virtual software were you thinking? Have you considered just virtualizing the two OS's, linux and windows? and not worrying about dual-booting? or is the cad sofware too hardware intense for a VM? What is the hardware on the mac?

You can install windows in bootcamp but VMs make more sense. I wouldn't install linux as dual boot because that'd void warranty.

So if you load Linux as a dual boot on a machine which has Window pre-loaded, you void the warranty?

If so, I've happily voided those warranties where microsoft don't even warrant that their software will even work.

should have been more clear, it voids warranty on an Apple Mac, if you install Linux.

Normal PCs would rarely ever have such a warranty on them but to be fair I just build the majority of my own machines anyways.

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You can run almost any distro in a VM. It doesn't matter 32 bit or 64 bit for this testing.

While you don't need swap in some cases it never hurts to have it. I tend to put the swap inside my virtual filesystem hard drive. It becomes transparent to the host. However you can usually put swap any location that your client can access on boot. One could make a virtual filesystem on any VM accessable location and use it as a swap.

When I say virtual filesystem I mean the type of file for your VM choice. I don't use that VM but I'd assume it has ways to make and add a file or group of files to act as the clients hard drive(s). The virtual hard drive in many cases can be set to grow as needed. You can assign 2tb and if the system only uses 16G then the space will never grow.

The same is true of some modern VM's and hardware. They are able to use ram better and you can overprovision it sometimes.

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I'm considering exactly that, although I do want the option of booting directly into Windows. I'm admittedly not entirely clear on the difference between a fully virtualized installation vs. installing on a separate partition and pointing the VM at it? Are these different, or are we discussing the same thing? Do you install from inside the VM to the same partition as the VM? What are the benefits? How difficult is it to change to a new version of Linux in such an approach, and how does virtualization impact file privileges?

In Windows, I want the option of greater performance, and in Linux, greater security. I want to gain familiarity with the Linux OS, and also for secure browsing for things like banking. (I had a serious security breach: Dropbox exploit, password re-use, the full domino effect.) To satisfy these two requirements, putting Windows on the SSD is imperative, while putting Linux on a separate partition on another drive may have advantages? How does virtualization impact security?

• The VM software I'm considering is Parallels Desktop.

• The hardware is Mid-2009 MBP, 2.66GHz dual core, and it will have SSD (500GB?) boot drive and probably a 7200 1TB drive as secondary. (Both will be limited by a Sata 2 bus, but there is evidence that Sata 3 hardware can max-out performance.) I don't want to sink too much money into the older device, but the alternative is significantly more expensive, and there are software expenses. I may choose a lesser expensive SSD.

• There are times where running ACAD in VM will probably be fine. Booting back and forth makes it difficult to multitask. Sometimes you just need to view or make a change, that's where the VM comes in. Without trying it, I can't be certain of performance. I need to educate myself on different virtualization approaches and the benefits of each.

• With Linux, I like that I can reinstall frequently without concern over data, and always have a secure drive/partition. There may be ways to optimize this for trials of new distros and also for security? (The obvious one that comes to mind is cloning the drive.)

The warranty ship sailed a long time ago. Why do you think they would single out Linux, but not Windows? The warranty is on the hardware, which is independent of the software. Apple support provides numerous, and helpful 'dual boot' articles on their website, including matrices about which models support which systems, etc. It is aimed at Windows users, most likely due to market demographics. (Supported through Win10.) Before performing repairs in store, the first thing they do is boot from an external for backup, before any diagnostics. What I'm doing now, hardware-wise, would no doubt violate the warranty--if I still had one.

Edit: Your warning is appreciated, but I'm committed to trying it. I don't think Linux will be the problem, although possibly the drivers. It can be reversed easily enough. The first step will be install new the new HDs and test it from a hardware standpoint, then once I'm confident that everything works, I will test each OS from an external boot drive before I proceed. (Where Linux may be a problem is if it tries to become the primary boot OS. That's why I want to put it on its own drive, if possible.)

Virtualization of memory seems to defeat the idea of swap memory, but perhaps I'm not understanding how that works. I would actually prefer a 'direct-boot only' installation of Linux to a 'virtual-only' scenario. I don't know enough about the VM file system to know if it could cause cross contamination. (I.e., is a VM of Linux vulnerable to problems/malware that affect the host?)

Ideally I would like Linux to be on the second drive. I'm having trouble finding documentation for the boot aspect of this. The installation of rEFInd is straightforward enough (install script). The part that isn't documented is how to tell it to find a Linux partition on the second drive? (One solution I saw, was to have the boot order be the second drive first, and the drive order, in that case Windows, to be Windows first. I'm hoping for a slightly less complicated method than this one, re: Arch linux. While I could follow the steps, I don't understand all of them.)

Edit: In re-reading this method, the biggest problem is changing the primary boot drive to be the second, or in my case the slowest drive. Hopefully there is a way to run the bootloader from the SSD in the main drive bay, and still boot Linux on the second drive (in the former optical bay).


Can you clarify accessible 'at boot'? Let's take the example of hibernation, can a hibernation image reside other than on the primary boot drive?

I understand why you are recommending a VM, after searching for how to do this. That said, I'm not sure a VM provides the same security features as a separately-booted partition.

You could have swap partitions and/or the (slightly less efficient) swap files...

Thanks. 1) Can it use both a file and partition at the same time? 2) Can different Linuxes share swap partitions? (A combination of partition and file would let me use the speed of the SSD, and the second drive for a larger swap to enable hibernate, and still have a data partition.)

I'm developing a better understanding of the multi-boot process, and in particular how rEFInd works. It autodetects the location of any installed bootloaders, including those on other drives. That should solve two problems, the possibility of booting Linux from a 2nd drive, and allocating space on the primary drive. I wanted room for shared data on the SSD, and Windows has a limitation of 4 partitions. I also want to be able to easily change distros without breaking my boot, and installing Linux on the 2nd drive would help (possibly a second Linux partition to experiment with other distros.)

I'm considering something like this (sizes approximate):


hda1/ MacOS (150GB)
hda2/ Windows (125GB)
hda3/ shared data (165GB)
hda4/ Linux (25 GB)

--

hdb1/ Linux swap (8GB) 2nd drive
hdb2/ data and backup (remainder of 1TB)

That gives me space on the main drive to adjust things.

What is not clear is if Grub needs to be installed to make Linux boot on the second drive, or do most Linux installers have their own boot loaders that will work with rEFInd?

I've never tried to share both a swap partition & swap file.

Multiple Linuxes can (and should) share the same swap partition.

Using a legacy boot - MBR - allows up to 3 primary partitions, one extended partition which contains an unlimited number of logical partitions.
AFAIK Linux could access all of these, but it is a very inflexible solution if you want loads of partitions.

If you have a recent PC, it should have a UEFI BIOS and this can hold up to 128 primary partitions.

There is a more sophisticated solution supported by most Linuxes - Logical Volume Management (LVM).
But its a bit tricky to use without prior Linux knowledge - it allows unrestricted partition resizing/creation/removal; actually it allows you to treat multiple disks as a single disk which can be divided into logical volumes.

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I hadn't considered sharing the file, only the partition. I suppose it could be possible if the file is somewhere accessible to all. (I may ultimately choose simplicity, and place all of the swap on the second drive to save write cycles on the SSD. It has 8GB RAM, and that will likely be enough, given what I'll be using it for.) The partition scheme will be as simple as possible. I'll be happy if I can get it booting. Thanks for your input.

I've been multibooting multiple decades. I've had 12 or more operating systems on 80GB HDs several times. Host m7NCD has 47 partitions on 160GB. / partitions for test installations can be 4800MB or less when used with separate /home/, /srv/ and /usr/local/ and limiting software installed to only what you'll actually use.