[Discuss] Stalwart E-mail; Was: Re: SSH options

[markw at mohawksoft.com (markw at mohawksoft.com)]

> Kent Borg wrote on 2026-01-21 08:00:
>
>> syncing between two e-mail servers but Courier cannot. I want that
>
> One technique I've seen discussed is to use iSCSI-backed storage for
> email, so both servers have read & write access to the same data which
> lives on different servers.
>
>
> Synchronization is one of those *hard* problems and this might bypass
> sync problems for "what if one storage server goes offline?" possible
> problems.
>
>
>
> I don't suppose it'd work with mbox storage, but Maildir should work
> quite well.

Let's nip this one in the bud. No, it won't work.

(1) iscsi is a block device protocol, it knows not anything about the file
system on it.
(2) Unless you implement locking across multiple accessors you will
corrupt the file system.

Even if you can guarantee that no two (or more) files will be accessed at
the same time, there are structures on the file system that will become
corrupt if multiple file system instances across different systems write
to the meta data at the same time.

iscsi is a terrible idea.

You might be able to get away with it on, say, NFS, but only if you enabe
locking. Simultaneous access to data from multiple writers is a complex
problem and iscsi doesn't manage any of it.