# Quota Roots

Quotas are applied to quota roots, which can be at any level of the mailbox hierarchy. Quota roots need not also be mailboxes.

Quotas on a quota root apply to the sum of the usage of any mailbox at that level and any sub-mailboxes of that level that are not underneath a quota root on a sub-hierarchy. This means that each mailbox is limited by at most one quota root.

For example, if the mailboxes

    user/bovik
    user/bovik/list/imap
    user/bovik/list/info-cyrus
    user/bovik/saved
    user/bovik/todo

exist and the quota roots

    user/bovik
    user/bovik/list
    user/bovik/saved

exist, then the quota root `user/bovik` applies to the mailboxes `user/bovik` and `user/bovik/todo`; the quota root `user/bovik/list` applies to the mailboxes `user/bovik/list/imap` and `user/bovik/list/info-cyrus`; and the quota root `user/bovik/saved` applies to the mailbox `user/bovik/saved`.

Quota roots are created automatically when they are mentioned in the setquota command. Quota roots may not be deleted through the protocol, see Removing Quota Roots for instructions on how to delete them.