AsyncMemberType indicates the async member is a disaster recovery (DR), read-only reporting, or read-write reporting async member.
0 - Disaster Recovery (DR). This is a disaster recovery async member. All its mirrored databases are read-only mirrored databases.
1 - Read-Only Reporting. This is a reporting async member. All its mirrored databases could be read-only or read-write databases. The default is read-only when the database is created.
2 - Read-Write Reporting. This is a reporting async member. All its mirrored databases could be read-only or read-write databases. The default is read-write when the database is created.
For more information, see the Async Mirror Members section of the chapter “Mirroring” in the Cache High Availability Guide
On the page System Administration > Configuration > Mirror Settings > Join as Async, fill in Mirror Information and select Next. On the page Async Member Information, in the Async Member System Type row, select a type from the drop-down list.