Merge #1982

1982: Change memory requirements r=mergify[bot] a=teadur

Running with ClamAV requires atleast 3GB of memory otherwise ClamAV updates fail and fill the disk https://github.com/Mailu/Mailu/issues/470

## What type of PR?

documentation

## What does this PR do?

### Related issue(s)
- Information from #470 

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.



Co-authored-by: Georg <teadur@users.noreply.github.com>
Co-authored-by: Dimitri Huisman <diman@huisman.xyz>

docs/compose/requirements.rst

@@ -5,8 +5,20 @@ Hardware considerations
 -----------------------
 
 You should make sure that your hardware (virtual or physical) is compatible with
-the latest Linux kernel. Also, you should have at least 2GB of total memory and
-1GB of free memory when running Mailu.
+the latest Linux kernel. The minimal required memory and swap are:
+
+* When using antivirus (clamav):
+
+  * 3GB of memory
+
+  * 1GB of swap
+
+* When not using antivirus (clamav):
+
+  * 1GB of memory
+
+  * 1GB of swap
+
 
 Pick a distribution
 -------------------

towncrier/newsfragments/470.doc

@@ -0,0 +1,4 @@
+Document hardware requirements when using clamav. 
+Clamav requires **at least** 2GB of memory.
+This 2Gb does not entail any other software running on the box.
+So in total you require at least 3GB of memory and 1GB swap when antivirus is enabled.