{
    "mode": "info",
    "parameter": "maildirquota",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/info/maildirquota/json",
    "generated": "2026-07-05T11:56:29Z",
    "synopsis": "maildirmake {-q} {10000000S} {./Maildir}",
    "sections": {
        "NAME": {
            "content": "maildirquota - voluntary Maildir quotas\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "maildirmake {-q} {10000000S} {./Maildir}\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "maildrop has a manual quota enforcement implementation that does use\nthe quota facilities of the host operating system (filesystem-based\nquotas). This is an option that is set at configuration time, and may\nbe disabled.\n\nUsing filesystem quotas sometimes leads to problems. After a hard quota\nis hit, most commands issued by mail clients fail, including some\ncommands that poorly-written mail software may not expect to fail, and\ntherefore be unable to gracefully handle the unexpected failure.\n\nWith manual quotas, the only operations that fail are the ones that\nmost mail clients expect to fail, when the mailbox is full. However,\nfilesystem-based quotas cannot be used in some situations, such as\nvirtual mailboxes. If this experimental feature is enabled, approximate\nquota enforcement can be implemented by maildrop or deliverquota to\nwhatever extent it's possible to do so. Quotas are enabled by the -q\noption to maildirmake. Both maildrop and deliverquota will observe any\nmaildirmake-requested quota.\n\nLIMITATIONS\nThis quota mechanism will only work as long as maildrop (or\ndeliverquota) are the only applications that deliver messages to the\nmaildir, or as long as other applications implement the same quota\nenforcement mechanism. The quota enforcement mechanism is described\nseparately in the README.maildirquota.html file in the source code\ndistribution.\n\nQuota enforcement will still work, to some extent, if there are other\napplications that deliver or modify messages in the maildir. However,\nquota enforcement may not kick in immediately when the maildir goes\nover quota, in fact the maildir can go over quota by a noticeable\namount. But eventually, as long as maildrop or deliverquota are\nresponsible for delivering the majority of messages, quota enforcement\nwill kick in. Also, other sources of messages may also result in\nnoticeable performance degradation, because quote recalculation will\nbecome noticeably more expensive.\n\nAlso keep in mind that this quota mechanism is generally useless if\nmail recipients have direct access to their maildirs.\n\nFinally even under the best conditions this quota enforcement does have\na small chance of a race condition where a maildir will go over quota\nby some amount. maildirs are designed for speed, and this quota\nimplementation was designed to have as little additional overhead as\npossible, compared to regular maildirs. To enforce an exact quota you\nwould have to use some kind of a locking facility, which will impose a\ndrastic performance degradation on the overall maildir performance. A\ndecision has been made to avoid locking, with the only negative side\neffect being a possibility of going over quota in very low probability\nsituations.\n\nA way to minimize the risk of going over quota is to set reasonable\nquotas, in relation to maximum message sizes supported by your mail\nserver. If you set your maildir quota to five gigabytes, for example,\nit makes very little sense to configure your mail server to accept\nmessages up to three gigabytes in size. Your maildir quota should be\nchosen so that it makes sense when compared to the maximum message size\nallowed by your mail server.\n\nFOLDERS\nThis quota implementation is compatible with a popular extension to\nmaildir which defines individual mail folders within a single maildir.\nHowever, in order to create a compatible folder, you MUST use the\nmaildirmake command that comes with maildrop, and you MUST use the -f\noption to maildirmake, giving the name of the folder. Do not use\nmaildirmake and specify the directory name of the maildir folder. Quota\nenforcement will not work if you do that.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "maildrop(1)[1], maildirmake(1)[2], maildropfilter(5)[3],\ndeliverquota(8)[4].\n",
            "subsections": []
        },
        "AUTHOR": {
            "content": "Sam Varshavchik\nAuthor\n",
            "subsections": []
        },
        "NOTES": {
            "content": "1. maildrop(1)\nhttp://www.courier-mta.org/maildrop.html\n\n2. maildirmake(1)\nhttp://www.courier-mta.org/maildirmake.html\n\n3. maildropfilter(5)\nhttp://www.courier-mta.org/maildropfilter.html\n\n4. deliverquota(8)\nhttp://www.courier-mta.org/deliverquota.html\n\nCourier Mail Server               07/24/2017                   MAILDIRQUOTA(7)",
            "subsections": []
        }
    },
    "summary": "maildirquota - voluntary Maildir quotas",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "maildrop",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/maildrop/1/json"
        },
        {
            "name": "maildirmake",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/maildirmake/1/json"
        },
        {
            "name": "maildropfilter",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/maildropfilter/5/json"
        },
        {
            "name": "deliverquota",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/deliverquota/8/json"
        }
    ]
}