partitioning advice.

[jquis8411]

Hello Ubuntu community:
I have desktop running 10.04 with a 160 GB HDD (150 ext4, 6.5gd swap) that is slowly becoming a file/print server. I decided to add a 500 gb hard drive and thought I should seek some advice before formatting and partitioning it. The network its on is shared with windows and Ubuntu machines. I do plan on adding more HDD's down the road as they fill up fast. I just didn't want to paint myself into a corner by not planning this out. TY

[srs5694]

If you expect to be making rapid changes, I recommend using an LVM configuration for the best possible flexibility. Unfortunately, Ubuntu makes LVM setup harder than it could be, but it can certainly be done. Try Googling "Ubuntu LVM" for some information.

The best approach is probably to set up a couple of smallish partitions for /boot partitions on the new 500GB drive (I say a couple so that you'll be able to do future OS installations more easily), set up the rest as an LVM, and transfer your current system into the LVM. When you're satisfied it's booting, you can then remove the partitions from the old 160GB drive, create a new LVM partition on it, and add it to the LVM. You'll then be able to add new disks as they become necessary, and remove smaller ones if you need to do so to make room for the new ones.

[holiday]

I was just looking into this for myself and found this great thing

http://ubuntuforums.org/showthread.php?t=282018

[jquis8411]

Thanks for the Link Holiday, I saw that and thought "I'm good to go". But I started looking into LVM now and it seems like a good idea, now this could be inexperience talking but with LVM could I just give each user their own shared volume to play with and set properties for it? And would LVM in anyway cause problems with Samba or SSH?

[srs5694]

Personally, I wouldn't give each user a separate logical volume in an LVM configuration; I'd just set up a single logical volume for /home and create accounts normally. If you need to limit how much disk space individual users are consuming, you can look into Linux's quota features. (Try Googling "Linux disk quotas" for information on this topic.) Quotas are much more flexible than using separate logical volumes for each user; there'll be less hassle to set up new accounts, and you can easily adjust quotas up or down as the need arises. (If you were to use separate logical volumes, you'd need to resize them to achieve such changes, and that would be both risky and more effort.)

LVM won't cause problems with Samba, SSH, or other servers; these servers all operate on a high enough level that they don't "see" such low-level details as the use of regular partitions vs. LVM, or even what filesystem is being used. (The servers will benefit or suffer from performance effects, of course, the same as any other program.)

[dino99]

mountmanager can help you set rights as you need

[holiday]

I had one LVM and did not enjoy the experience, but perhaps I didn't give it enough of a try. I'll read up on it, but perhaps someone could give a rationalization for using them, or give us some reasons to not.

[jquis8411]

I did see some things that recommended against using LVM with the desktop edition of Ubuntu, I was not sure if it was just some bad luck or something though because I cant imagine what the difference between the server edition and desktop would be, except a GUI of course.

[srs5694]

I had one LVM and did not enjoy the experience, but perhaps I didn't give it enough of a try. I'll read up on it, but perhaps someone could give a rationalization for using them, or give us some reasons to not.

Reasons to use LVM:

• Easily combine space from smaller disks or disk fragments into a big filesystem. For instance, if you've got three 80 GB hard disks, you can create a single filesystem that's up to 240 GB in size.
• Increase speed in multi-disk setups by using LVM's striping feature, which interleaves one filesystem across two or more disks, thus spreading the load and increasing performance.
• Easily add, delete, and resize logical volumes without having to adjust other filesystems. For instance, in a conventional partitioning scheme, if you've got /dev/sda1, /dev/sda2, and /dev/sda3, in that order on the disk, and if you want to delete /dev/sda1 and add the space to /dev/sda3, you've got to move /dev/sda2 -- a potentially time-consuming and risky task. If all three filesystems were in LVM, you could do the equivalent without touching the LVM equivalent of /dev/sda2. This is because LVM works a lot like a filesystem, and logical volumes are like files -- they can be discontiguous, unlike partitions, which must remain contiguous.
• Add future disks to a current LVM setup, enabling expansion of existing partitions into the new disk space without creating new mount points, moving files, etc.
• Delete old disks from a current LVM setup without having to explicitly juggle files. (This assumes there's sufficient free space in the LVM to absorb the storage space being lost by deleting the old disks.)

Reasons to avoid LVM:

• Increases complexity of setup; normally, you'll use LVM atop normal partitions, which adds to the set of tools you need to use. Even if you use LVM without a partition table, LVM tools are more numerous and complex than partitioning tools like fdisk or GParted. (OTOH, LVM GUI utilities can simplify its configuration, so this isn't really all that huge a drawback.)
• Increase the risk of data loss -- if one disk fails, recovering data from the other disk(s) can be difficult. Using LVM atop a suitable RAID setup can minimize this risk, but at the cost of added complexity. AFAIK, TestDisk can't recover the individual logical volumes within an LVM. (I don't know offhand if TestDisk can identify and recover a lost LVM partition.)
• GParted can't resize logical volumes; however, other GUIs, such as kvpm and system-config-lvm, can do the job instead. (This is therefore a minor drawback, but I mention it because GParted is well understood by the Ubuntu community as a whole, whereas the LVM GUI tools are not as well understood.)
• Booting from LVM may require a separate /boot partition. (True of GRUB Legacy; not true of GRUB 2.) This is a very minor issue, since you can easily create a suitable partition when you install or convert to LVM.
• The Ubuntu installer provides poor LVM support, making initial LVM setup by newbies very difficult. (Note that this isn't true of all distributions. Fedora, for instance, provides LVM support in its installer that makes it pretty easy to set up LVM.)
• Non-Linux support for Linux's LVM is poor, so if you want to create a shared-data partition, it will have to reside outside of the LVM, thus reducing the flexibility of the system overall. That is, if you want to change the size of the shared-data partition, you'll have all the usual partition-management headaches, and transferring space between a shared-data partition and a logical volume can be still more complex.

There are probably other issues for both the "pro" and the "con" lists; these are just the issues that sprang immediately to mind.

Personally, I like LVM. Four of my six Linux installations use LVM. I am, however, an advanced Linux user. If Ubuntu provided Fedora's level of LVM support, I'd say that even newbies should consider using it; but as it is, new Ubuntu users are usually best served sticking the conventional partitions. I recommended it to jquis8411 because s/he plans to add disk space in the future, perhaps multiple times in the future. That's the sort of dynamic system for which LVM provides significant benefits.

[jquis8411]

Well I grabbed LVM2 from synaptic and it doesn't look all that intimidating.(but I have only known how to cut and paste for less than a year so I'm prob a poor judge) But here is my plan so far, 1) on the new HDD (500GB) create a boot partition, but Im not sure how big. 2) Make all the remaining space one big LVM partition which I can then break down into smaller logical volumes as I see fit. 3)figure out how to get my stuff (OS included) off the old HDD and onto the new one, then create another LVM partition on the old HDD and tie it all together..Hows this sound, Am I on the right track?