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My disk is running full so I checked server logs and largest files and everything is ok. IOTOP also fine. I deleted 1 GB of files for testing purposes and it takes a minute until the disk runs full again so something is clearly writing although I cant see what via iotop.

Inodes df -ih is also fine - not completely used

Here is a picture. Strangely it says that only 318GB out of 335GB is USED but 0% is available:

Picture of disk usage

Then I checked the control panel and the VPS is currently snapshotting. Can a snapshot feature use disk space as temporary storage or is that running entirely on external drives?

Thank you for your input, much appreciated

Paul
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mashup
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1 Answers1

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By default Linux (presumably, though other unix do it too) partitions reserve 5% of the disk space as "root only", to prevent the user clogging the disk to the point that system administration its self becomes impossible.

That 5% is factored into to DFs reports, so df will report the disk at being 100% full when its at 95% full, which yours is if you do the maths.

You can disable the reserved space depending on your filesystem, e.g. tune2fs is probably the tool for you.

The snapshotting by the virtual machine manager, being part of the hypervisor operations, should be pretty much undetectable by the VM its self, and have no effect on available space the VM can see / use.

Figuring out what's using up the space seems mostly like a job for DU, or you can lsof, I don't know if you can find throughput by file, probably, but 'du' (even if you end up resorting to diffing them) probably finds you whats going on.

Though, as with the above, you can speculate its not a root process (or is a root process that drops privs by suid-ing down to a user account) since it hasn't consumed the final reserved 5%. Assuming it isn't just where it happened to stop naturally.

Iain Price
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  • The 5% reserved space is a feature of ext2/ext3/ext4. There are other file systems supported by Linux which do not have that feature. It isn't `df` that takes it into account. The 5% are subtracted by the file system driver before the number is given to `df` in the first place. – kasperd Jan 01 '17 at 22:27