Exchange 2019 Mailbox Services

Flashcards covering Exchange 2019 mailbox services, database file structures, ESE technology, maintenance tasks, and high availability concepts.

Backend role

The core role in Exchange 2019 that hosts mailboxes and processes transport and client access services.

Stateless proxy services

Front-end services where clients are authenticated before their data is processed at the back-end.

Mailbox Database (.edb)

The primary storage file used for storing mailbox data.

Tmp.edb

A temporary storage file used for database operations.

Transaction Log Files

Files (e.g., E00.log) that use hexadecimal numbering to record transactions in memory before they are flushed to the database.

Checkpoint File (E00.chk)

A file that tracks committed changes by pointing to the last flushed transaction.

Reserved Log Files (E00res)

Files used to protect the system against disk full issues.

Extensible Storage Engine (ESE)

A high-performance, reliable database engine used by Microsoft services such as AD, DHCP, and Exchange.

ACID Principles

The four properties of transactions followed by ESE: Atomic, Consistent, Isolated, and Durable.

Write-Ahead Logging

The process where transactions are created in memory, logged first to disk, and later flushed to the database to protect integrity during power failures.

Checkpoint depth

The amount of uncommitted data residing in memory, which defaults to approximately $100\,MB$ per database in Exchange 2019.

Clean Shutdown

A database state where the database was detached cleanly and no recovery is needed.

Dirty Shutdown

An incomplete database state that requires a transaction log replay to become mountable.

ESEUTIL /MH

An ESE utility command used to show the current state (Clean or Dirty Shutdown) of a database.

ESEUTIL /R

The command used to replay transaction logs to recover a database from a Dirty Shutdown.

ESEUTIL /P

A manual repair command intended as a last resort that carries a risk of mailbox data loss and invalidates logs and checkpoints.

Archive Mailboxes

Long-term storage separate from the primary mailbox that can offload older mail using retention policies, enabled via Enable-Mailbox -Archive.

Soft deletes

Deleted items that are moved to the Deleted Items Folder.

Hard deletes

Deleted items that are moved to the Recoverable Items area.

-RetainDeletedItemsUntilBackup $TRUE

A setting that ensures recoverable items are not purged until a successful backup has completed.

Online Maintenance

A process scheduled by default from 1 AM to 5 AM to perform garbage collection of deleted items, content index cleanup, and database optimization.

Background Database Maintenance

A continuous ESE process that performs checksumming, page scrubbing, and index repair to detect early database corruption.

Issue Warning Quota

The storage threshold, defaulted at $1.9\,GB$, at which an Exchange user receives a notification.

Prohibit Send Quota

The storage threshold, defaulted at $2.0\,GB$, at which an Exchange user is no longer allowed to send mail.

Prohibit Send/Receive Quota

The default storage threshold of $2.1\,GB$ at which an Exchange user is prohibited from both sending and receiving mail.

Database Availability Group (DAG)

A group of 2 to 16 mailbox servers that provides high availability through block-level replication.

Block-level replication

A replication method that provides near real-time synchronization for database copies across DAG members.