No space to create more partitions, but there is free space
 

Hey guys. I rarely get to load a new server, so I was going through setting up my slices, first made /, then /boot, then swap as primary partitions, then when I went to make /home even though I had like 130GB free space, it said I didnt have space available.

Couple questions:
What am I most likely doing wrong that it's telling me there's no space? It's CentOS if that matters.
Primary partitions are just ones that could be bootable, so am I picking the right ones to mark as primary?

Well, probably the partition-table is full. Print out the list of partitions and be sure you didn't mess one up. Research "extended partitions."

Could there be some existing partition on the drive?

Not sure that is exactly true. Some things could change that would allow almost any number of os's to be booted to a single drive.

When I got to the partitioning screen, first thing I did was delete everything. Then I setup those 3 on the internal drives on the server, then it wouldn't let me do any more. But it did let me setup partitions on an external array after that, so must just be something with doing more on the internal drives.

Please post the output of on that server, run as root.

I run that while booted off the centos dvd?

Yes, this way we can see what exactly is the situation with your disks.

do you know how I do that from the CD? I've never done it before

If you're in the graphical installer, press ctrl-alt-F2 to switch to a VT with a shell prompt.

okay thanks. I will try it next time I get to the server and post what it says

Yeah... "and relax... no rocket-science here... it's only ones and zeros." ;) The partition-table is just "a table," located in the first sector of the drive and known to the controller hardware. It has a fixed number of entries, but (in the usual "we never thought we'd run out ... now what do we do?" Engineering Hack), the last entry can be a (tah, dahhh!) "extended partition" which can contain "more partitions." ("Whew! That was close!")

Once you boot the CD and run parted on the drive, it will tell you exactly what the partition-table now contains. From there, you can easily see your way to setting-up whatever you want.

Chances are you're hitting the 4-partition limit in the table. The partition table only allows 4 partitions in it, however one of those four can be an extended partition, which allows other partitions inside (odd, I know). If you're only going to have 3 partitions, you can make 3 primary and be fine. If you're going to have 4 or more partitions, you should set up 3 primary and 1 extended, with the rest of your partitions inside the extended.

You've only mentioned setting up 3 partitions and then encountering an error when attempting to set up the fourth. This shouldn't be a problem, but perhaps there's already a 4th hidden partition that you're not seeing in the GUI. That's why everyone here is asking to see the output of parted -l.

side question: now that I've done Alt+Ctrl+F2 to get to the shell prompt, how do I get back to the installer GUI?

OK, here's what I'm seeing when I do parted -l:

Under my /dev/sda, which is the RAID1 of the 148GB drives on the server where i'm trying to make all my slices. I'll list the number, size, type, file system, flags columns for each, figure the start & end isn't important for now
partition table: msdos
1, 524MB, primary, ext4, boot
2, 146GB, primary,*blank*,lvm

Then I have 4 volumes after that for my external RAIDs, all of which are the entire space, they have partition table:msdos with each using the full space as ext4 and primary for Type.

I don't think I need/want to use LVM, as these "system" partitions are going to be fixed sizes, but I can't say I'm totally up on the pros/cons of LVM either.

Thanks for all the help everyone, I'm REALLY trying to learn Linux, but I can't even get past setting up partitions apparently haha.

I should probably say what I'm trying to do as well. I want to have each of these be their own slice

/
/boot
swap
/home
/tmp
/opt
/usr
/var

That way if one fills up, it won't bring all them down. We've had /var fill up before I'm told :(

You can have either 4 primary partitions, or three primary and on one extended, with the extended partition divided up into as many logical partitions as you like.

As other have said, your description doesn't track with the actual limits, so there is something else there which you haven't described. Unless you post better detail on what is there, we can't give better detail on what to fix.

In Linux logical partitions can be bootable. There is no significant difference in behavior or capability between a primary partition and a logical partition. If you wanted, you could allocate the entire drive as one extended partition, with no primary partitions, then allocate all your partitions as logical partitions.