Transcript 4-member DAG 4 databases 4 copies of each database 4 databases per volume Symmetrical design DB2 DB3 DB4 Active Passive Lagged.

4-member DAG
4 databases
4 copies of each database
4 databases per volume
Symmetrical design
DB2
DB3
DB4
Active Passive Lagged
Single database copy/disk:
Reseed 2TB Database = ~23 hrs
Reseed 8TB Database = ~93 hrs
20 MB/s
DB1
DB1
DB1
Active Passive Lagged
Single database copy/disk:
Reseed 2TB Database = ~23 hrs
Reseed 8TB Database = ~93 hrs
4 database copies/disk:
Reseed 2TB Disk = ~9.7 hrs
Reseed 8TB Disk = ~39 hrs
12 MB/s
DB2
20 MB/s
DB3
20 MB/s
DB4
12 MB/s
Active Passive Lagged
X
Periodically
scan for failed
and
suspended
copies
Check
prerequisites:
single copy,
spare
availability
Allocate and
remap a spare
Start the seed
Verify that the
new copy is
healthy
Admin
replaces failed
disk
AutoDagDatabasesRootFolderPath
AutoDagVolumesRootFolderPath
Configure storage
subsystem with spare disks
Create DAG, add servers
with configured storage
Create directory and
mount points
Configure DAG, including 3
new properties
MDB1
Create mailbox databases
and database copies
AutoDagDatabaseCopiesPerVolume = 1
MDB1
MDB1.DB
MDB2
MDB2
MDB1.log
MDB1.DB
MDB1.log
http://aka.ms/autoreseed
Parameter
Description
BeginSeed
Useful for scripting reseeds. Task asynchronously starts the seeding operation and then
exits the cmdlet.
MaximumSeedsInParallel
Used with Server parameter to specify maximum number of parallel seeding
operations across specified server during full server reseed operation. Default is 10.
SafeDeleteExistingFiles
Used to perform a seeding operation with a single copy redundancy pre-check prior to
the seed. Because this parameter includes the redundancy safety check, it requires a
lower level of permissions than DeleteExistingFiles, enabling a limited permission
administrator to perform the seeding operation
Server
Used as part of a full server reseed operation to reseed all database copies in a F&S
state. Can be used with MaximumSeedsInParallel to start reseeds of database copies in
parallel across specified server in batches of up to value of MaximumSeedsInParallel
parameter copies at a time
Exchange Server 2010
Exchange Server 2013
ESE Database Hung IO (240s)
System Bad State (302s)
Failure Item Channel Heartbeat (30s)
Long I/O times (41s)
SystemDisk Heartbeat (120s)
MSExchangeRepl.exe memory threshold (4GB)
Exchange Server 2013 CU1
Bus reset (event 129)
Replication service endpoints not responding
Cluster database hang (GUM updates blocked)
All Healthy
Server that has all health sets in a healthy state
Up to Normal Healthy
Server that has all health sets Medium and above in a healthy state
All Better than Source
Server that has health sets in a state that is better than the server hosting the affected copy
Same as Source
Server that has health sets in a state that is the same as the server hosting the affected copy
cas1
cas2
Redmond
cas3
cas4
Portland
Assuming MBX3 and MBX4 are operating and one of them can lock the witness.log file,
automatic failover of active databases should occur
mbx1
mbx2
Redmond
dag1
witness
third datacenter: Paris
mbx3
mbx4
Portland
mbx1
mbx2
Redmond
dag1
mbx3
mbx4
Portland
1. Mark the failed servers/site as down: Stop-DatabaseAvailabilityGroup DAG1 –ActiveDirectorySite:Redmond
2. Stop the Cluster Service on Remaining DAG members: Stop-Clussvc
3. Activate DAG members in 2nd datacenter: Restore-DatabaseAvailabilityGroup DAG1 –ActiveDirectorySite:Portland
mbx1
mbx2
Redmond
dag1
mbx3
mbx4
Portland
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