If I dual boot install both Ubuntu and Windows, is it safer to install them on two different hard drives than different partitions on the same hard drive?
What risks may be involved? For example, one OS does not recognize the files of another OS. One OS accidentally wipes out the other OS by some system operations?
06 Answers
In general, they should leave each other alone. If you do the install correctly (Windows first, then Linux, as a rule, because Linux is more 'considerate'). As far as I am aware, there is no additional risk involved in sharing a drive.
Having said that, here are some gotchas to watch out for.
Windows will not be able to see the contents of your Linux drive or partition, unless you install additional software. ext4fsd works for me.
Shared storage partitions. If there is a partition which both OSes can see natively, meaning FAT32 or NTFS, then there can be issues with data loss. If Windows goes into hibernation, and another OS makes changes to the shared partition, Windows will tend to undo the changes when it is resumed. I recommend either external storage, or disabling hibernation on Windows, or both.
UEFI. This is new with Windows 8. There are two types of firmware interface, BIOS (older) and UEFI (newer). Both operating systems need to be installed using the same one. You can find a much more in-depth explanation here.
It is safer to use 2 hard disks.
during formatting it is easier to recognize the different hard disks. 1 will be named sda and the other sdb. Though the installer puts names next to bootable partitions it does help to find other partitions that belong to that specific OS (like a D: drive will be sda2 on sda where sda1 is the OS for Windows or db2 is a partition for sdb where sdb1 is the root for Ubuntu).
hard drive failure. Does one drive fail you take it out and still boot into the other OS (maybe with the help of GRUB recovery).
I myself though would install the bootable partitions (ie. the operating system (C: and /)) on the fastest hard drive and put my data on the other drive.
But... backups and being able to restore them is more important. The best thing to do is make regular backups of your important data. If you do that you will only have minor problems.
7Short answer:
It doesn't matter at all.
Detailed answer:
There is absolutely no risk with keeping two operating systems on the same disk device. You can mess with another system partition as long as the disk device with that partition is accesible, putting it on separate physical device doesn't make it safer (nor less safe) in any way.
3If you have two hard drives, then installing Windows on one and Ubuntu (or any other OS) on the other is the most convenient.
most modern Windows PC's come with three partitions already installed - a recovery partition, the "System Reserved" partition, and finally your primary Windows partition. If only 3 Primary partitions are defined, create an extended partition and install Ubuntu there.
Assuming Windows consumes your entire first hard drive, then you must resize those Windows partitions.
There is a sense of security when installing the second OS on a separate hard drive. With two hard drives, you can just slip the primary one out (in the case of a laptop) or disconnect the power (for a desktop). Now you know that you are not going to accidentally corrupt your main OS while installing the other. For the truly paranoid, you can do the same when upgrading to newer versions.
E.g. My machine supports four hard drives; so I run Windows 7 on the primary and Ubuntu on the second. Rather than use the Linux boot loader to select my OS, I simply use the BIOS boot screen to choose to boot from the first or second hard drive. If I press the power button and walk away, then it boots from the primary disk unattended.
Ubuntu will be happy to mount your Windows partitions so that you can access your files.
Another option to consider is to use a virtual machine. I use VMware on my Windows partition The only caveat is that you need enough memory and CPU power to run both OS's simultaneously.
One comment about redundancy - if you plan to set up any kind of disk redundancy (mirroring or RAID-5 striping) you need to have hard drives of close to the same size to avoid wasting space (the system will use the size of the smallest drive). A hardware approach is much more reliable and performs better than a simple software-based solution. You MUST back up any data you do not want to lose!
1From a strict system point of view, it is exactly the same ... provided you correctly configure your partitions. Correctly configured partitions are perfectly safe to use and you will never inadvertantly erase date in one partition while working on another one - be they under same OS or not.
If you configure them by hand hacking the Master Boot Record with low level tools ... it depends on your proficiency with such tools ! But if you use high level tools to resize partitions and create next, you should not get into trouble.
As you asked for a safer way, my advice would be to split both disks with one Windows partition and one (or more) Ubuntu ones on each. That way, you could easily duplicate sensitive data on a second disk for any OS. You could even build a RAID-1 mirror for your (or one of your) Ubuntu partition(s). But I must admit it is a rather advanced configuration if you cannot afford (or do not want) to duplicate everything.
7It would statistically be less safe to install onto two separate drives. If one drive fails you lose half of your data. Conversely, installing both OSs to one drive and keeping the (hypothetical?) second drive as a backup drive would give you a form of redundancy should one drive fail.
As far as your system is concerned, it doesn't matter if you partition one drive twice and install both operating systems there or install onto two separate drives.
Install both correctly and there is no danger of one OS wiping the other. You will likely need to grant access from each OS to the other if you want to share files between systems.
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