Storage-Side MetadataΒΆ

When saving data to object storage, Dovecot stores metadata associated with each blob for data recovery purposes.

This data is written to the HTTP endpoint by adding Dovecot metadata headers to the request. When retrieving a message from object storage, this data is returned in the received headers (only parsed by Dovecot if needed).

The header name used is specific to the obox driver:

Driver

Metadata Header

azure

x-ms-meta-dovecot_<key>

s3

x-amz-meta-dovecot-<key>

sproxyd

X-Object-meta-dovecot-<key>

swift

X-Object-Meta-<key>

The metacache keys available are:

Key

Description

Max Length (in bytes)

Data Type

Other

username

Dovecot unique username

N/A (installation dependent)

email

guid

Message guid

32

email

size

Message size (in bytes)

20 (in theory; rarely more than 10)

email

received

Received date (unix timestamp)

20 (in theory; rarely more than 10)

email

saved

Saved date (unix timestamp)

20 (in theory; rarely more than 10)

email

pop3uidl

POP UIDL

N/A (depends on source installation)

email

Only if message migrated

pop3order

POP message order

10

email

Only if needed by migration

origbox

Folder guid of first folder where

stored(copying does not update this)

32

email

fname

Dovecot filename

N/A - installation dependent (username component)

email

Dictmap only

username

Dovecot unique username

N/A (installation dependent)

index

size

Bundle size (in bytes)

20 (in theory; rarely more than 10)

index

fname

Dovecot filename

N/A - installation dependent (username component)

index

Dictmap only

mailbox-guid

Mailbox guid the index refers to

32

index

Dictmap only

username

Dovecot unique username

N/A (installation dependent)

fts

fname

Dovecot filename

N/A - installation dependent (username component)

fts

Dictmap only