Core Advanced Settings

Warning

These settings should not normally be changed.

See Settings for list of all setting groups.

mail_cache_min_mail_count

Only update cache file when the mailbox contains at least this many messages.

With a setting other than 0, you can optimize behavior for fewer disk writes at the cost of more disk reads.

mail_cache_unaccessed_field_drop

  • Default: 30days

  • Values: Time

Specifies when cache decisions are downgraded.

Changed in version v2.3.11: Change caching decision from YES to TEMP after this much time has passed. Drop the field entirely after twice this much time has passed (i.e. 60 days by default), regardless of whether the cache decision was YES or TEMP previously. Older versions used this setting only for dropping the field after it hadn’t been accessed for this long.

See Mail Cache Settings for details.

mail_cache_record_max_size

  • Default: 64k

  • Values: Size

If a cache record becomes larger than this, don’t add it to the cache file.

mail_cache_max_size

New in version v2.3.11.

  • Default: 1G

  • Values: Size

If dovecot.index.cache becomes becomes larger than this, it’s truncated to empty size. The maximum value is 1 GB because the cache file format can’t currently support large sizes.

mail_cache_purge_min_size

  • Default: 32k

  • Values: Size

Only compress cache file if it is larger than this size.

mail_cache_purge_delete_percentage

Compress the cache file when n% of records are deleted (by count, not by size).

mail_cache_purge_continued_percentage

Compress the cache file when n% of rows contain continued rows.

For example 200 means that the record has 2 continued rows, i.e. it exists in 3 separate segments in the cache file.

mail_cache_purge_header_continue_count

Compress the cache file when we need to follow more than n next_offsets to find the latest cache header.

mail_index_rewrite_min_log_bytes

  • Default: 8k

  • Values: Size

Rewrite the index when the number of bytes that needs to be read from the .log index file on refresh is between these min/max values.

See mail_index_rewrite_max_log_bytes

mail_index_rewrite_max_log_bytes

  • Default: 128k

  • Values: Size

Rewrite the index when the number of bytes that needs to be read from the .log index file on refresh is between these min/max values.

See mail_index_rewrite_min_log_bytes

mail_index_log_rotate_max_size

  • Default: 1M

  • Values: Size

Always rotate transaction log after it exceeds this size.

See also:

mail_index_log_rotate_min_age

  • Default: 5mins

  • Values: Time

Rotate transaction log if it is older than this value and is larger than mail_index_log_rotate_min_size.

See mail_index_log_rotate_max_size

mail_index_log_rotate_min_size

  • Default: 32k

  • Values: Size

Rotate transaction log if it is larger than this size and is older than mail_index_log_rotate_min_age.

mail_index_log2_max_age

  • Default: 2days

  • Values: Time

Delete .log.2 index file when older than this value.

Older .log.2 files are useful for QRESYNC and dsync, so this value should not be too low.