in the near future we would like to offer a groupware service to our customers (small an medium-sized businesses). Our service should scale up to 10.000 Users and more. Zimbra looks very interesting for that. At the moment we are looking at the system requirements for our service. We think that nowadays you have to offer large mailboxes with 25 GB each to be competitive. Google Apps Professional Edition, Microsoft Online Services and 01.com (Zimbra!) providing 25 GB mailboxes.
To get 25 GB mailboxes at an affordable price it is very important to select the right storage model and storge components. I think it is all about DAS vs. SAN and SATA vs. SAS.
I already searched through the forum. It looks like most people are recommending SAN-based systems for large deployments using a combination of SAS and SATA drives with Hierarchical Storage Management. This is of course not the most expensive solution but maybe also not the cheepest one.
I found a Document for Microsoft which is describing the same situation for MS Exchange systems. The title is "Exchange 2010 Large Mailbox Vision Whitepaper". It can be found here:
Download details: Exchange 2010 Large Mailbox Vision Whitepaper
As far as I understand, in this document MS recommends using multiple servers with a DAS storage attached to each server. They seem to use cheep SATA drives with 1 TB only. They say they can use cheap drives because
a) MS Exchange Server 2010 has lowered IOPS/user to 0,1 and
b) with large mailboxes of 2 GB each you have 500 users per disc which is fine
Because the server are replicated they get a lot of capacity, high availability and no need for backups.
My question is: does the MS approach apply to Zimbra as well? What do the experts in this forum think about the right way of deploying large mailboxes with low budget?