Best CentOS partition layout

I like the idea of having / , /boot , /var and swap. That way logs and Dovecot index files in /var won't use up other disk space on the system, or count towards domains' quotas.

Also, having /tmp on a separate partition can also be useful, so that temp files don't overwhelm the system, and can be excluded from quotas.

Yeah, you don't want to do too many partitions, as they you can run into the problem of not having enough space on one while you've got plenty on another.

Making /tmp noexec is kind of pointless in my opinion - by the time an attacker has got to the point of being able to write to /tmp, you are in big trouble anyway! Also, it can break the Virtualmin install script.

Personally I wouldn't even bother with /home, but some people like it in order to isolate user disk usage from the rest of the system.

Ok, if you have plenty of space, making /home a separate partition is quite reasonable..

Three questions:

a) Not assigning /tmp a separate partition could distort quota usage because data which is of no use (from the user's point of view) would be accounted to the user's quota?

b) User database storage use is not covered by Virtualmin quota settings, regardless of having mounted /var on a separate partition or not?

c) If we want an accurate (as good as possible) quota management/measurement, we sould use the following partitions: /boot, /, /swap, /var, /home, /tmp ?

Thanks for your advice.

a) Yes, that is correct. On the other hand, having /tmp as a separate partition could allow users to fill it up with no restrictions.

b) If the partition for /var/lib/mysql is the same as /home, Virtualmin will make MySQL data files owned by the domain's group, so they will participate in quota limits. However, if they are not the same filesystem it can still count disk used by MySQL for each domain, and send warning emails about it.

c) That seems OK, as long as you don't care about hard enforcing quotas on MySQL disk usage.

c) That seems OK, as long as you don't care about hard enforcing quotas on MySQL disk usage.
Did I get it right: Does hard enforcing mean, that the OS will enforce quota settings, i. e. that a database will not - under no circumstances - exceed a given quota, whereas, when the databases reside on a partition different than that of /home, there is no such hard enforcement so that quotas won't be enforced but there will be at least a warning?

Would it then be wise to work with four partitions

/boot
/swap
/
/home with /var/lib/mysql symlinked to /home/mysql ?

If quota usage is of importance, could you make a suggestion on how to partition a system with a 250 GB disk, that should serve as an allround server (htttp, e-mail, ftp) based on Debian?

Yes, your explanation is correct.

Linking /var/lib/mysql to /home/mysql is a good work-around for this. You can then keep /var as a separate partition, for logs.

It sounds like you guys are all talking past one another.

Different filesystems have separate quota tables. You will not get quota enforcement for any data that is not on the same filesystem as /home.

If you want everything that a user can create to be under the control of the quotas you set, you need one filesystem for all user-created files. Thus, /home, /var, and /tmp would all need to be on the same filesystem (and partition or volume).

We can't tell you what is "best", because it depends on your requirements and how much you care about enforcing usage limits over other factors (like the possibility of quotas preventing some actions from happening, as Jamie mentioned above).

I can say that I prefer to use as few partitions as possible. The simplest partition layout described in the documentation is the one I always use. As the documentation points out, the majority for reasons for breaking things up into many partitions simply don't apply to modern hardware and operating systems.

All the above configurations are correct in different situations.

What I have learned during my quest for fine tuning over the years.

If you are using quota on a particular directory, it should must be mounted to a partition alone so all remaining file creation processes may not generate false alarms.

In VM case /home must be a separate partition not to be shared with any thing else.

SWAP & tmp are obviously separate partitions,

VAR & /USR/LOCAL & /OPT & /BOOT & last / can be a separate partitions

But still it all depends what your are doing & what is required in a given situation.

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