Quotas and limits
Several independent limits keep the tenants of the shared infrastructure apart. They differ in scope and in what happens when you reach them; knowing which one you're looking at saves debugging time.
Account-level resources
Your account as a whole is capped on:
| Limit | Covers |
|---|---|
| Storage | Everything under your home directory: website files, application data, logs, and mail storage, plus your databases and mailing list archives. |
| Memory, CPU, I/O | All your processes together: app servers, containers, cron jobs, and terminal sessions. |
| Process count | How many processes can run at once. |
Resource Usage shows your use against each cap; Processes shows what's using them right now.
At the memory or process cap, a process usually fails to start or is stopped by the system. Look at those two pages first.
Mailbox quotas
Each mailbox has its own disk quota, set per domain user and separate from your account storage. A full mailbox refuses new mail with a clear temporary failure to the sender; your other mailboxes and your website aren't affected.
A quota stops a mailbox from growing past a size; it never makes one smaller. To recover space from a mailbox nobody reads, also set a retention period. See Delete old mail.
Mail sending limits
Two separate sending limits are always in effect. An empty setting means "use the default", never "unlimited".
| Per-sender limit | Per-account sendmail limit | |
|---|---|---|
| Applies to | Each mailbox and each send-only account. | Mail your programs hand to the system sendmail command: PHP's mail(), a contact form, a cron job. |
| Scope | That one sender. | One shared bucket for all your sites and domains, since such a send has no mailbox login of its own. |
| Over the limit | Delayed or temporarily refused; it recovers on its own. | Refused and dropped; the direct path has no queue to hold it. |
| Where a refusal appears | Nowhere separate. | Sendmail Failures. |
Sending limits exist for one common reason: a burst of outgoing mail usually starts with a compromised password or script, and an uncapped sender can destroy a domain's reputation in minutes.
Raise that sender's limit rather than working around it. The sendmail
default, set per account by your provider, is generous enough for normal
application mail; it caps a runaway program, not ordinary sends.
Lockdown
Lockdown is for a mailbox you judge compromised: it stops the mailbox from sending, invalidates existing sessions, and resets the credentials, issuing a new welcome link to the user. The panel keeps each domain user's lockdown history. See Manage domain users.
Mailing list limits
Your provider also sets four limits for mailing lists:
| Limit | Default | When you reach it |
|---|---|---|
| Mailing lists | 100 per account | The panel refuses a new list. |
| Members per mailing list | 10,000 per list, whatever their status | The panel refuses the new members, adding none of the addresses you gave. |
| Addresses at a time | 1,000 in one Add Members or one API request | The panel refuses the whole paste. Add the addresses in smaller parts. |
| Message size | 10 MB per post | The mail server refuses the post. |
The panel and the API tell you which limit you reached and its value. Each list's page shows its members against the limit and the largest post it accepts.
The list sends one copy of a post to each member. A 10 MB post to 1,000 members is 10 GB of outgoing mail.
AI budget
The AI Assistant runs against a usage budget your provider grants: a spending allowance that refills over time.
- No budget: the assistant is off for the whole account.
- Empty budget: the assistant pauses until it refills.
- Either way, you can still read past conversations.
Where the limits come from
Your hosting provider sets all of these per account. Mailbox quotas you set yourself, within your allowance.
If a limit doesn't fit your workload, talk to your provider. There's no way around it: the limits are enforced below the level your processes run at.