[Dovecot] Better to use a single large storage server or multiple smaller for mdbox?

[Emmanuel Noobadmin]

On 4/9/12, Stan Hoeppner <stan at hardwarefreak.com> wrote:
> So it seems you have two courses of action:
> 1.  Identify individual current choke points and add individual systems
> and storage to eliminate those choke points.
>
> 2.  Analyze your entire workflow and all systems, identifying all choke
> points, then design a completely new well integrated storage
> architecture that solves all current problems and addresses future needs

I started to do this and realize I have a serious mess on hand that
makes delving in other people's uncommented source code seem like a
joy :D

Management added to this by deciding if we're going to offload the
email storage to a network storage, we might as well consolidate
everything into that shared storage system so we don't have TBs of
un-utilized space. So I might not even be able to use your tested XFS
+ concat solution since it may not be optimal for VM images and
databases.

As the requirements' changed, I'll stop asking here as it's no longer
really relevant just for Dovecot purposes.

> You are a perfect candidate for VMware ESX.  The HA feature will do
> exactly what you want.  If one physical node in the cluster dies, HA
> automatically restarts the dead VMs on other nodes, transparently.
> Clients will will have to reestablish connections, but everything else
> will pretty much be intact.  Worse case scenario will possibly be a few
> corrupted mailboxes that were being written when the hardware crashed.

> A SAN is required for such a setup.

Thanks for the suggestion, I will need to find some time to look into
this although we've mostly been using KVM for virtualization so far.
Although the "SAN" part will probably prevent this from being accepted
due to cost.

>> My lame excuse is that I'm just the web
>> dev who got caught holding the server admin potato.
>
> Baptism by fire.  Ouch.  What doesn't kill you makes you stronger. ;)

True, but I'd hate to be the customer who get to pick up the pieces
when things explode due to unintended negligence by a dev trying to
level up by multi-classing as an admin.

> physical network interface.  You can do some of these things with free
> Linux hypervisors, but AFAIK the poor management interfaces for them
> make the price of ESX seem like a bargain.

Unfortunately, the usual kind of customers we have here, spending that
kind of budget isn't justifiable. The only reason we're providing
email services is because customers wanted freebies and they felt
there was no reason why we can't give them emails on our servers, they
are all "servers" after all.

So I have to make do with OTS commodity parts and free software for
the most parts.