Out of space on mostly empty disk.

[owlcroft]

When trying to install, via Synaptic, either the latest acroread update or the latest kernel upgrade (to 2.26.27-14), I encounter the dreaded "failed in buffer_write(fd) (10, ret=-1)" error. I don't know Unix well, and I don't understand where the problem lies, as most of the disk is empty.

Having searched out a few threads, I can offer these data. First, both regular and Root Trash are empty. Second, /var has 6.0 GB free: there is nothing big in /var/backups or /var/log.

Next, the output of df -h :


df -h

Filesystem Size Used Avail Use% Mounted on

/dev/sda5 1012M 1001M 0 100% /
tmpfs 1005M 0 1005M 0% /lib/init/rw
varrun 1005M 332K 1005M 1% /var/run
varlock 1005M 4.0K 1005M 1% /var/lock
udev 1005M 2.7M 1002M 1% /dev
tmpfs 1005M 616K 1004M 1% /dev/shm
lrm 1005M 2.4M 1003M 1% /lib/modules/2.6.27-11-generic/volatile
/dev/sda3 96M 26M 66M 28% /boot
/dev/sda9 190G 2.1G 179G 2% /home
/dev/sda8 20G 173M 19G 1% /tmp
/dev/sda7 9.9G 3.2G 6.2G 35% /usr
/dev/sda6 6.8G 478M 6.0G 8% /var


Next, the output of du -hc --max-depth=1 (hand-sorted by size):


du -hc --max-depth=1

6.2G .
3.1G ./usr
1.9G ./home
677M ./media
335M ./var
246M ./lib
26M ./boot
14M ./etc
12M ./root
9.9M ./sbin
7.3M ./bin
4.4M ./lib32
3.3M ./dev
80K ./tmp
16K ./lost+found
4.0K ./opt
4.0K ./srv
4.0K ./mnt
0 ./proc
0 ./sys
cannot access `./home/eric/.gvfs': Permission denied

6.2G total


The root partition (apparently sda5) seems 100% full, yet the directories under it are mostly empty.

Can anyone give me some clear, explicit instructions on what I can do here?

Thanks!

[merlinus]

From what I can see, you only gave about 1G for /. It needs at least 4-5G in order for you to do much of anything.

Post a screenshot of gparted to make sure, and look at possibilities, e.g. using some of the huge space of /home for /.

[RJARRRPCGP]

I encounter the dreaded "failed in buffer_write(fd) (10, ret=-1)" error.

That error looks suspicious, likely a bad HDD or a loose HDD connector.

Or a loose USB drive.

[owlcroft]

From what I can see, you only gave about 1G for /. It needs at least 4-5G in order for you to do much of anything.

Post a screenshot of gparted to make sure, and look at possibilities, e.g. using some of the huge space of /home for /.

http://owlcroft.com/GParted.png

Considering that there are separate partitions for /var, /user, /home, and /tmp, what would it likely be that eats up so much space in the root?

And, in any event, what--in precise detail for a dummy--ought I best to do about it?

Thanks!

[merlinus]

Why do you need separate partitions for /var, /user, /tmp, and even for /boot?

The easiest solution is to back up important data and do a fresh install. Give / 10G, depending on how may apps you intend to install. 1.5G for /swap is plenty, and you can either give all the rest to /home, or create a /data partition as well.

Neither of the last two needs to be formatted upon reinstall or install of a new version, so your data, application configurations and settings, email, and so on will be fine.

Also, I would have one primary partition, in the event that you might need such in future, and then create an extended partition for the rest of the hdd, with logical partitions within that.

[owlcroft]

Is there any alternative to a re-install?

Also, any idea what it is that is eating so much space?

Before installing, I reviewed a great number of articles about how to allocate partition space. I no longer remember the reasoning--though doubtless I have the texts saved somewhere--but what I eventually used seemed the optimum. With those separate partitions, the root itself--from what I read--would need only a fraction of 1 GB, but Ubuntu won't install at less than 1 GB for root.

Of course, the Ubuntu habit of retaining all older kernels sopmewhat expands the needed space, but I still am unsure whence the problem.

[merlinus]

The alternative is lots and lots of changes within gparted, and a huge amount of time to do same, because you can only add continguous space to /, and the obvious solution of shrinking /home and adding the freed-up space to / will therefore not work.

You would have to delete and/or move /tmp, /var, and /user before you could do anything that would work long-term.

In future, even after reading articles, how-to's and other people's experiences, a post on the forum serves as a reality check.

Also, if you look in filesystem, you will see many other directories that take up many gigs, e.g. etc, proc, lib, lib32, opt, sys.

[owlcroft]

. . . Also, if you look in filesystem, you will see many other directories that take up many gigs, e.g. etc, proc, lib, lib32, opt, sys.
Well, I'm puzzled. So far as I can see, the directories encompassed in / (that is, which do not have partitions of their own) are:



du -hc --max-depth=1 Folder properties in Nautilus

246M ./lib 5,912 items, totalling 231.5 MB
677M ./media 19 items, totalling 71.1 KB
14M ./etc
12M ./root
9.9M ./sbin
7.3M ./bin
4.4M ./lib32
3.3M ./dev
16K ./lost+found
4.0K ./opt
4.0K ./srv
4.0K ./mnt
0 ./proc
0 ./sys

And those, between them, sum to something a hair under 1.0 GB, which, I suppose, is why the / partition seems full.

But . . . though when I look with the file browser, the /lib directory is more or less in line with the du readout (231.5 MB vs. 246 M), the /media values are wildly diferent: du says 677M, whereas clicking the Properties of the /media folder shows contents of 71.1 KB. That's about 2/3 of a GB that I don't understand.

Also: could I somehow use a symlink to some subdirectory in, say, /home? Something like symlinking /media to /home/media ?

Being unclear on symlinks, would a symlinked directory replace the original (meaning before setting the link I'd have to copy over everything), or does it simply augment it?

[owlcroft]

Well, I got it figured out.

The extra 675 MB or so was stashed away in the /media folder: it was a backup thumb memory stick that somehow--as I said, I don't understand Linux very well--apparently had everything from the stick on the hard drive as well, right there in /media/BackUpFolder. Why clicking on the folder Properties in Nautilus told me that the contents of /media were about 71K I have no idea. But deleting the subfolder left / at about 335MB--the "a few hundred megabytes" all the partition-size docs had cited--and allowed all the upgrades to proceed smoothly.

I guess I have a lot to learn about using rsync with thumb drives, but for now the system is otherwise just fine.

Thanks, everyone, for the various suggestions.