Capacity Planning for Resellers

Why This Matters

Poor capacity planning is one of the most common and costly mistakes resellers make. Running out of storage on a subscription forces you to migrate client accounts, which is expensive, time consuming, and largely your responsibility to handle. A little planning goes a long way.

Allocated Storage vs Actual Usage

These are not the same thing, and confusing them is a common pitfall.

Allocated storage is the total storage you have promised to your clients across all their accounts. If you sell ten clients a 10GB mailbox each, you have allocated 100GB.

Actual usage is how much storage your clients are actually consuming at any given moment. Those same ten clients might only be using 15GB combined if their mailboxes are relatively empty.

Reseller subscriptions have a hard storage limit based on actual usage, not allocated storage. This is what makes overselling possible — and also what makes monitoring essential. If actual usage creeps up unexpectedly, you can hit your limit well before you expect to.

When to Act

As a general guideline, when a subscription reaches 50% of its storage quota it is time to purchase a new subscription and begin placing new clients there. Stop adding clients to the original subscription entirely by the time actual usage reaches 100GB, regardless of the subscription tier.

These are conservative guidelines, not rules, and have served resellers well. Resellers selling smaller per-client packages may find they can comfortably go higher before needing to act. Monitor your usage and act before you are forced to, as failure to do so may be costly as described below.

Requesting Same-Server Provisioning

New reseller subscriptions may be provisioned to a different server than your existing one, and this is by design based on our system design. While you can request that a new subscription be provisioned on the same server, it cannot be guaranteed, nor can the request always be granted. Multi-server management is an inevitable reality of scaling your reseller business — whether it happens on your second subscription or your hundredth, plan for it from the start. See Managing Clients Across Multiple Servers for guidance on how to set up your DNS correctly across multiple servers.

When purchasing a new subscription, make the request for same-server provisioning before adding any clients to it.

How Your Client Mix Affects Your Thresholds

No two resellers are the same. A reseller selling large mailboxes of 25GB or more per client will hit capacity much faster than one selling 1GB to 5GB packages. A mixed portfolio requires tracking both client count and actual usage patterns carefully.

There is no formula that fits every situation. The right time to act depends on how quickly your clients are filling their mailboxes, how many new clients you are adding, and what you have allocated versus what is actually being used. The only reliable approach is to monitor your usage actively and consistently.

Overselling

Overselling means allocating more storage to your clients than your subscription physically contains, based on the assumption that actual usage will remain well below the total allocation.

Overselling is permitted and widely practiced. Many successful resellers operate at oversell ratios of 10:1 or higher — for example, a 200GB subscription with 2TB of total allocated storage across all clients. This works as long as actual usage stays within the subscription limit.

The risk is that actual usage can grow faster than expected, particularly if clients accumulate large attachments or long email histories over time. Overselling aggressively while continuously adding new clients without monitoring actual usage is how resellers end up in trouble.

The Cost of Poor Planning

If actual usage on a subscription fills up and clients need to be moved, your options depend on where your subscriptions are located.

Accounts on the same physical server can in most cases be transferred between reseller subscriptions for a small fee, as a courtesy from MXroute. This is not a service to be relied upon as a routine part of managing your business.

If your subscriptions are on different servers, the migration falls entirely on you. MXroute does not generally assist with cross-server migrations, and when we do it is only in rare cases when support volume allows, which in practice is nearly never. When such assistance is available, it starts at $105 per account migrated.

The cost of an additional subscription is far less than the cost of a migration. Plan ahead.