Hi, with the mdbox storage one needs to regularly run purge to really clean up deleted mails from the storage. Running purge can be an IO intensive task as the files are append-only and even if in a 10 MB mdbox file only a small mail is deleted all other mails need to be copied to a new file. Therefore, I wonder whether there is the option to apply a threshold before a mdbox file is cleaned up, e.g. only purge an old mail if this affects > 10% of the mdbox filesize or if at least X bytes will be freed in an mdbox file. Is this possible ATM? Otherwise this can be seen as a feature request. Best, Sven PS: From the docs it's unclear to me how the mdbox rotating algorithm works. Is only to the latest mdbox file appended or it is possible that a small mail might be appended to an older mdbox file?