How Does Ubuntu Manage Multiple Hard Drives?

[turkey3_scratch]

In Windows you have C:/ for your one hard drive, and another might be something like D:/ but in Ubuntu everything simply starts with / and I am curious as to how it handles the naming of multiple hard drives?

 

[skittle]

in unix/linux there are multiple ways of handeling HDDs and partitions.
The archwiki and debian wiki have some more info
https://wiki.archlinux.org/index.php/persistent_block_device_naming

 

[Ijack]

Linux has a single filesystem, with its root at /. You add new devices to this filesystem by "mounting" them on directories. ( http://oreilly.com/openbook/debian/book/ch04_04.html ) This is unlike Windows where, conventionally, disks are set up as separate filesystems. Not many people realize it, but Windows can work in the same way as Linux, mounting disks or partitions on directories.

 

[ebpollock]

Pay attention to the UUID, its a long alpha numeric string, I have found it is easier to work with it when defining mount points especially if the disks may move from system to system and the drive name, sda1 for example may change when plugged into another port. Short answer is it manages drives very well with more options which might take a little reading to figure out. Creating RAID arrays is also simple. Also pay attention to permissions for the disk and set them accordingly.

 

[turkey3_scratch]

Linux has a single filesystem, with its root at /. You add new devices to this filesystem by "mounting" them on directories. ( http://oreilly.com/openbook/debian/book/ch04_04.html ) This is unlike Windows where, conventionally, disks are set up as separate filesystems. Not many people realize it, but Windows can work in the same way as Linux, mounting disks or partitions on directories.

Oh, so on WIndows how the OS is only on one hard drive, alteratively on Ubuntu the OS can be accross multiple hard drives?

 

[Ijack]

Although, normally, Windows itself is installed on a single drive or partition it is possible to do otherwise. The same is true of Linux, though it is more common there - especially on high-performance systems - to use multiple disks.

It's really just a logical difference.

 

[skittle]

Yes for example if you have an small SSD. On my c720 I run Linux. /boot and / are on the 16GB SSD (/dev/sda1 and /dev/sda2). /home is on a 64GB SD card (/dev/sdb). /boot is ext4, / is btrfs with LZO compression, and /home f2fs.

The same could be done on Windows. c:/ on the SSD and have Documents and Settings on d:/

 

[Ijack]

That's how my Windows 7 is set up (except that it's G:/ rather than D:/). As a more extreme example, you could even have part, or most, of the OS on a networked drive. You don't even need a hard disk to run Windows or Linux.

 

[turkey3_scratch]

But could you have /home on about 3 hard drives?

 

[skittle]

Though experiment:
One mount point, three HDD's. You write a file to /home, which HDD does it get written to?
In general you have one block device per mount point.

Ways around this limitation:
1)Use RAID for the 3+ HDDs, then they appear as one block device and can all be mounted to /home. RAID takes care of where data is written.
2)Mount separate users on /home to separate HDDs.
/home/skittle on /dev/sdb
/home/turkey3_scratch on /dev/sdc
/home/ijack on /dev/sdd