Tài liệu Module 4: Troubleshooting the Recovery Storage Group ppt

...3 Creating a Recovery Storage Group ...7 Adding a Mailbox Store to the Recovery Storage Group ...10 Active Directory Attributes...17 Lab 4.1: Create a Recovery Storage Group and revie

Contents

Introduction 1

What is the Recovery Storage Group? 3

Creating a Recovery Storage Group 7

Adding a Mailbox Store to the Recovery Storage Group 10

Active Directory Attributes 17

Lab 4.1: Create a Recovery Storage Group and review the Active Directory attributes 20

Overriding the Recovery Storage Group 25

Restoring the data 27

Recovering Exchange 2000 Server Mailbox Stores 33

Exmerge 35

Known issues with Exmerge 48

Exercise 2: Recovery Storage Group Scenario 1 50

Exercise 3: Recovery Storage Group Scenario 2 54

Details for Exercise 3: Disaster recovery after a Store Crash using the Recovery Storage Group 55

Acknowledgments 58

Module 4:

Troubleshooting the Recovery Storage Group

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In Exchange 2000 Server, we required the use of an alternate Active Directory forest/Exchange org to recover data without affecting the production

environment

The Recovery Storage Group is designed to simplify the data recovery process and lower the TCO for customers by eliminating the need for hardware for an alternate recovery forest

The Recovery Storage Group allows us to restore production Mailbox Stores to live servers Once the restore has been performed, we can use Exmerge to merge the data back into the live stores

We will look at the process of recovering data and also the sort of issues we can run into and how to solve them

Mailbox Recovery in Exchange 2000 Server

Exchange 2000 Server required the use of a separate Active Directory forest in order to restore databases and recover mail items without affecting the

production system in any way

A typical recovery scenario would be:

A server crashes and a mailbox store cannot be mounted The transaction logs are still available After unsuccessfully attempting to get the store to mount, the administrator would take copies of any log files and database files from the time of the crash and then mount blank databases so that the users could log in and send/receive mail

A separate Active Directory forest would then have to be set up and a new Exchange organization would have to be created in this forest The following information must remain consistent with the production environment:

„ Exchange Organization Name

„ Administrative Group Name

„ Storage Group Name

„ Logical Database Name

„ LegacyExchangeDN The administrator must also ensure that the Operating System and Exchange have the same service packs and hot fixes as the production machines

When the administrator has done this, he could start the restore of the databases

to this recovery server

Once the restore was complete and any log files have been replayed, the database would be at a consistent state The administrator would then use a utility like Exmerge to export the data to pst files and then import it into the live database

The option of switching the recovered databases from the alternate forest with the blank databases in production is also available This will reduce the amount

of time required to Exmerge data back to the production server

This is obviously a fairly long process and in larger environments, it meant that customers would have to maintain a separate Active Directory forest for this purpose

The recovery steps for Exchange 2000 Server are explained in

813337.KB.EN-US

A Microsoft Support Webcast goes into great detail on this subject:

„ Support Webcast: Microsoft Exchange 2000 Alternate Server Data Recovery

us;811063&gssnb=1

http://support.microsoft.com/default.aspx?scid=kb;en-What is the Recovery Storage Group?

The Recovery Storage Group is a new type of Storage Group that can be created on servers running Exchange Server 2003 in order to facilitate Mailbox data recovery

An existing Mailbox Store can be added to a Recovery Storage Group and then recovered while the original database is still online

The Mailbox store is not physically added to the Recovery Storage Group A placeholder object is created in the Recovery Storage Group that is used as a reference back to the original Mailbox Store We will look at this in more detail later

Exmerge is then used to merge the recovered information over to the production Mailbox Store

A Recovery Storage Group can be created on both Standard and Enterprise editions of Exchange Server 2003

Recovery Storage Groups will work irrespective of the Operating System that Exchange Server 2003 is installed on

Restrictions and criteria

Recovery Storage Group has the following restrictions/criteria:

„ One Recovery Storage Group per server can be created

„ Five Mailbox Stores can be added to the Recovery Storage Group

„ Only mailbox stores from the same Admin Group can be added to the Recovery Storage Group

„ Once a mailbox store has been added, only mailbox stores from the same original Storage Group can be added to the Recovery Storage Group

„ An Exchange 2000 Server mailbox store can also be added to an Recovery Storage Group but it must be a minimum of SP3

Note

„ In order to add a Mailbox Store to the Recovery Storage Group it must exist

in the Active Directory

„ All restores will default to Mailbox Stores that are in the Recovery Storage Group, not to the live database (Note: The backup client must be pointed to the server hosting the Recovery Storage Group)

„ There is a registry key to override this behaviour (“Recovery SG Override”) (See Section 7)

„ Mailbox Stores in the Recovery Storage Group do not mount on up/failover

start-„ By default the “This database can be overwritten by a restore” is checked on recovery databases

„ Public Folder Stores cannot be added to a Recovery Storage Group

„ New Mailbox Stores cannot be created in a Recovery Storage Group

„ When the Mailbox Store is mounted, all mailboxes remain disconnected and cannot be reconnected

„ No new mailboxes can be created on a recovery database

„ MAPI is the only protocol that is supported

„ When the Mailbox Store in the Recovery Storage Group is mounted, you will receive a warning (prompt)

„ The log file prefix for the Recovery Storage Group is Rnn

„ On an Active/Active cluster (2 Node) we can create one Recovery Storage Group per cluster

„ On an Active/Passive cluster we can create one Recovery Storage Group per Exchange Virtual Server (EVS)

„ Mailbox Stores from standalone servers can be added to an Recovery Storage Group on a clusters and vice versa provided they are in the same Administrative Group

„ No online maintenance will be run on recovery databases

„ System and Mailbox policies are not applied to recovery databases

„ Recovery Storage Groups cannot be renamed

„ Recovery Databases cannot be backed up

„ In order to successfully Exmerge out the data for a particular user, their mailbox must exist on the same mailbox store as of the time of backup

To recover Public Folder databases, the alternate forest method is still required

Note

Recovery Storage Group uses

There are two key scenarios where the Recovery Storage Group is useful The first occurs when we need to recover a certain number of mail items without affecting the production environment This may be an important piece of mail for a CEO or a mailbox that was removed due to an administrative error

The second scenario occurs when we run into a critical problem with the production mailbox stores A customer’s Mailbox Store or a particular log file may become corrupted, which results in a store that will not mount A Service License Agreement may dictate that after a certain number of hours users must

be able to send/receive mail In this situation the Administrator would probably move out all databases and log files and then mount blank databases The recovery of mail data could then begin offline

The two most common scenarios can be broken down as follows:

Recover Mail items for a particular user

A user contacts the IT helpdesk and needs a piece of data recovered that they deleted from their mailbox The item is not available in the dumpster The Administrator will then use the following steps to recover the mail item using a Recovery Storage Group:

„ Create a Recovery Storage Group on any server in the Admin Group Add the mailbox store to the Recovery Storage Group

„ Restore the data to the Recovery Storage Group server and mount the Mailbox Store

„ Use Exmerge to export the data and then to import it directly into the user’s mailbox

„ Dismount and delete Mailbox Store in the Recovery Storage Group Delete the Recovery Storage Group

Mount blank Mailbox Stores due to corrupt store

The steps to recover in this manner are as follows:

„ Mailbox Store becomes corrupted and cannot be mounted Move out all log files (assuming no other databases are mounted in the storage group) and the corrupted database files

„ Mount blank databases Users can log in and send/receive mail

„ Create a Recovery Storage Group on any server in the same Admin Group

„ Restore a backup of the Mailbox Store to the Recovery Storage Group server If you wish to replay any log files you must place them in the Transaction Log Path of the Recovery Storage Group

„ When you initiate a hard recovery of the mailbox store, it will start replaying log files from the backup set (usually from a path that is specified

at the time of restore) and then continue replaying log files from the Transaction Log Path

„ When the mailbox store has been recovered, we are ready to switch it back

to live storage group

„ Dismount the Mailbox Store in the Recovery Storage Group and the Mailbox Store in the live Storage Group Switch the databases with each other and then remount them again

„ We then use Exmerge to export/import the new data from the clean databases we created

„ When the Exmerge is finished, dismount and delete the mailbox store in the Recovery Storage Group Delete the Recovery Storage Group

The reason for switching the databases with each other is so that we Exmerge the minimum amount of data The blank mailbox stores will hold a relatively small amount of data compared to the live mailbox store so it makes sense to only Exmerge this data This is, of course, a matter of preference and there is nothing to stop you Exmerging over the larger amount of data to the new databases

Remember that when Exmerging large amount of data, lots of transaction logs are generated so there must be sufficient disk space on the server

Creating a Recovery Storage Group

Using Exchange Server 2003 System Manager we now have a new choice when creating Storage Groups on an Exchange 2003 server As well as normal Storage Groups, we can now create Recovery Storage Groups

The steps to create a Recovery Storage Group are as follows:

Right-click on the chosen server object in Exchange System Manager and

choose New – Recovery Storage Group

The Recovery Storage Group Properties sheet will now be displayed Here

we can specify a name for the Recovery Storage Group It is a good idea to use

a name that clearly identifies it as a Recovery Storage Group as the icon in Exchange System Manager for a Recovery Storage Group and a normal Storage Group are the same

The Recovery Storage Group must have a unique name on the server It cannot have the same name as a normal Storage Group that is already in use on the server The name of the Recovery Storage Group does not have to match the name of the Storage Group that hosted the Mailbox Store that we are about to restore

Specify the Transaction log location and the System Path Location using the

browse buttons This location cannot be changed afterwards

The Transaction log location and System path location should NOT be set to

the same as an existing Storage Group on the Exchange 2003 server To try and simplify the whole process, use the same paths for the transaction logs, system path and database files

As almost no data is written to Mailbox Stores mounted in a Recovery Storage Group, there will be very few transaction logs generated Therefore, there is no real performance gain by splitting the transaction logs and database files onto separate drives (This is contrary to normal best practices regarding normal

Storage Groups in Exchange 2000 Server and Exchange Server 2003)

When the Recovery Storage Group has been created, we can check its default

settings by taking the properties of the newly created Recovery Storage Group

Note that the Transaction log location and System Path Location cannot be

changed If you must change these locations, then you can simply delete the Recovery Storage Group, create a new one, and then specify the correct paths

The Log File Prefix is set to R00 by default This cannot be changed

Circular Logging cannot be enabled on a Recovery Storage Group

A Recovery Storage Group cannot be renamed If you must use a different name for your Recovery Storage Group then you will have to delete it and recreate it

Adding a Mailbox Store to the Recovery Storage Group

Once the Recovery Storage Group has been created, Mailbox Stores that need

to be recovered can be added to it

In Exchange System Manager 2003, right-click on the Recovery Storage Group

and choose Add Database to Recover Notice that there is no option to create

new databases in a Recovery Storage Group

In a mixed Exchange 2000/2003 environment, you will need to be using Exchange System Manager 2003 in order to create and manage a Recovery

Storage Group

The Select database to recover dialog box will then be presented Here we will

be presented with a list of eligible Mailbox Stores The criteria for eligible Mailbox Stores are as follows:

„ The Mailbox Store must exist in Active Directory

„ The Mailbox Store must be hosted on a server within the same Administrative Group

„ The Mailbox Store must be from a server that is running a minimum of Exchange 2000 Server SP3 and a maximum version no higher than the server where the Recovery Storage Group resides

„ If a Mailbox Store already exists in the Recovery Storage Group, then only

Mailbox Stores from the same original Storage Group will be presented

Notice that the version of Exchange is quoted and the fact that databases from later versions of Exchange and versions earlier than Exchange 2000 Server SP3 will not be shown

Choose the desired Mailbox Store and click OK

If we attempt to add a Mailbox Store to the Recovery Storage Group

when there are no more eligible Mailbox Stores, then the Select database to

recover will NOT be shown and we will see the following error:

This error basically means that we have previously added a Mailbox Store to the Recovery Storage Group and there are no more Mailbox Stores available from the same original Storage Group

Check the contents of the Recovery Storage Group to see if you have a Mailbox Store there and remove it if necessary

If there is no Mailbox Store in the Recovery Storage Group, have a look at the Recovery Storage Group object using LDP or ADSIEdit If there are any Mailbox Stores listed there, delete them and try again

Failing that, delete the Recovery Storage Group and try to add the Mailbox

Store again

Note

The Mailbox Store Properties sheet will now be shown

On the General tab notice the default settings We must now give the Mailbox

Store a name This will always default to the display name of the Mailbox Store

in the Active Directory This can, however, be changed to whatever you like

Notice which settings are disabled by default

On the Database tab we can see the default settings

Notice the Exchange database and Exchange streaming database default

settings These database names are generated using the display name on the

General tab In some cases this will not match the databases names of the live

Mailbox Store in production

For example the default Mailbox Store on an Exchange 2003 server has the following properties:

Database Name: Mailbox Store (SERVERNAME)

Exchange Database File: Priv.edb

Streaming Database File: Pub.edb

If you were to add this Mailbox Store to a Recovery Storage Group, the default

settings would create a Mailbox Store with the database names “Mailbox Store

(SERVERNAME).edb” and “Mailbox Store (SERVERNAME).stm”

These database names do NOT have to match those of the live database in

order for the restore to be successful This matching is handled by an attribute

called MsExchOrigMDB We will look more closely at this attribute in the

Active Directory attributes section later

The Maintenance Interval cannot be set for a Mailbox Store in the Recovery

Storage Group

Mailbox Stores in the Recovery Storage Group will not mount at startup (or

after failover in a cluster) This cannot be changed By default “This database

can be overwritten by a restore” is checked It must remain checked for a

successful restore

Click OK when you are done

Active Directory Attributes

Now that we have created a Recovery Storage Group and added a Mailbox Store to it for recovery, we can take a closer look at the inner workings of the Recovery Storage Group and how the various parts fit together

There are several new Active Directory attributes to identify the various components that make up the Recovery Storage Group

the following error:

This MsExchMaxRestoreStorageGroups attribute can be viewed using a tool like LDP or ADSIEdit

The image below shows the new user interface (UI) for the Windows

2003 version of ADSIEdit

This value can be seen by drilling down to the following location:

CN=InformationStore,CN=EXCHANGESERVER,CN=Servers,CN=First Administrative Group,CN=Administrative

Groups,CN=ORG,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain,DC=com

Note

Be aware that this value can also be changed using one of these tools

If this value were changed to 2, for example, then we would be able to create two Recovery Storage Groups on the server However, when we try to perform

a restore to this server, the restore would fail and the following Event ID would

be generated in the application log:

If you are seeing more than one Recovery Storage Group on an Exchange 2003 server then this attribute has almost certainly been changed manually Any extra Recovery Storage Groups should be deleted and this value should be set back to

1

Note

Lab 4.1: Create a Recovery Storage Group and review the Active Directory attributes

Objective:

To understand the Active Directory attributes that make up the Recovery Storage Group

Exercise 1

1 Log into Z3 using the credentials above

2 Start Exchange System Manager

3 Drill down to ORG - Administrative Groups - Hubsite – Z3- First Storage Group Notice that we have only the default Mailbox Store and Public Folder Store on this server

4 Right-click on the Z3 server object and choose New - Recovery Storage Group

5 The Recovery Storage Group properties page now appears

6 Leave the name as the default setting and also leave the Transaction Log Location Path and System Path Location as the default settings Notice that the Enable Circular logging option is grayed out

7 Click OK We now have a Recovery Storage Group on Z3 Notice that you cannot change the name or location of the Recovery Storage Group after it has been created

8 Right-click on the Recovery Storage Group and choose Add Database

to Recover

9 Notice that all Mailbox Stores in the Administrative Group are now displayed Notice that the X500 Distinguished name of each of the Mailbox Stores are also displayed

10 Choose the Mailbox Store (Z3) and then click OK The properties page for the Mailbox Store to be added will now appear Accept the default settings and click OK

11 We now have Mailbox Store(Z3) in the Recovery Storage Group

12 Start ADSIEdit by clicking on Start, then Run Type Adsiedit.msc in the field and click OK

13 Drill down to the following location:

Configuration - CN=Configuration - CN=Services - CN=Microsoft Exchange - CN=ORG - CN=Administrative Groups - CN=Hubsite - CN=Servers - CN=Z3 - CN=Information Store

14 Right-click on CN=Information Store and select Properties

15 Locate the attribute MsExchMaxRestoreStorageGroups and click on it Its value is 1 This attribute is used to determine the maximum number of Recovery Storage Groups that can be created on

double-an Exchdouble-ange 2003 server It should not be chdouble-anged from 1

16 Drill down to the following location: Configuration - CN=Configuration - CN=Services - CN=Microsoft Exchange - CN=ORG - CN=Administrative Groups - CN=Hubsite - CN=Servers - CN=Z3 - CN=Information Store - CN=Recovery Storage Group

17 Right-click on CN=Recovery Storage Group and select Properties

18 Locate the attribute MsExchRestore Its value should be TRUE This is used to identify the Storage Group as a Recovery Storage Group If you were to check the attribute on an ordinary Storage Group, its value should be <NOT SET>

19 In the right-hand pane, locate the Mailbox Store CN=Mailbox Store(Z3) Right-click on it and select Properties

20 Locate the attribute MsExchRestore Its value should be TRUE This is used to identify the Mailbox Store as a recovery store that is part of an Recovery Storage Group

21 Locate the attribute msExchOrigMDB Its value should be set to the Distinguished Name (DN) of the original Mailbox Store (This was visible in Step 9) This attribute is used to link the recovery mailbox store back to the original Mailbox Store When performing an online restore to the Recovery Storage Group, this DN must match the DN of the mailbox store on the media

MsExchRestore (on Storage Group)

This is an attribute of all Storage Groups in Exchange Server 2003 The

attribute is a Boolean value and possible values are TRUE, FALSE and Not

Set

The attribute is used to distinguish a Recovery Storage Group from a normal

Storage Group On a Recovery Storage Group the attribute is set to TRUE and

on a normal Storage Group its value is Not Set It can be seen by using either LDP or ADSIEdit

If this value is changed to FALSE or NOT SET then the Recovery Storage

Group will effectively be converted to a normal Storage Group It is not

recommended to change the values of Storage Groups in this manner

MsExchRestore (on Mailbox Store)

This is a Boolean value attribute of all Mailbox Store objects in Exchange

Server 2003 Possible values are TRUE, FALSE or Not Set

The attribute is used to distinguish a Mailbox Store that is hosted in a Recovery Storage Group from a Mailbox Store that is hosted in a normal Storage Group When a Mailbox Store object is created in a Recovery Storage Group this

attribute is set to TRUE The value is NOT SET on a Mailbox Store that is hosted in a normal Storage Group

If this attribute is changed in any way on a recovery Mailbox Store, then the Recovery Storage Group may function unpredictably

This is not an attribute of a Public Store

Note

MsExchOrigMDB

This is a string value attribute of all Mailbox Store objects in Exchange Server

2003 A Mailbox Store that is hosted in a normal Storage Group will have the

attribute set to <not set> When a Mailbox Store is added to a Recovery

Storage Group this attribute is set to the Distinguished Name of the original Mailbox Store

This attribute is used to link the new Mailbox Store Active Directory object in the Recovery Storage Group back to its original Mailbox Store

In order for an online restore to be successful, the MsExchOrigMDB attribute

must match the distinguished name of the Mailbox Store in the backup set

If no Mailbox Store is found in the Recovery Storage Group with a matching

MsExchOrigMDB attribute then the restore will fail with a 9634 error

Overriding the Recovery Storage Group

If there is no Recovery Storage Group present on an Exchange Server 2003 server, then restore behaviour is exactly the same as in Exchange 2000 Server

If there is a Recovery Storage Group present on the server then all restores will default to mailbox stores that exist in the Recovery Storage Group If a

Recovery Storage Group is present on the server and you attempt to restore a mailbox store that is not part of the Recovery Storage Group you will receive the error shown below:

This behavior can be overridden by setting the following registry key:

HKLM\System\CurrentControlSet\Services\MSExchangeIS\Parameters System\Recovery SG Override

DWORD value = 1

If this registry key is set to 1 then the Recovery Storage Group is ignored and restores will be targeted at the mailbox stores in the ordinary storage groups on the server

The Information Store service does not have to be restarted for this registry setting to take effect The Information Store will recognize its existence immediately

This registry key would typically be used if an Administrator wishes to perform

an online restore of one of his production databases without disturbing the databases in the Recovery Storage Group

Note

Restoring the data

Once the Recovery Storage Group has been created and the mailbox store added to it, the restore process can begin

When starting the backup client software it is important to remember that the client software must be pointed to the Exchange 2003 server that contains the Recovery Storage Group with the placeholder Mailbox Store object in it Using the Recovery Storage Group we can perform an online restore of the Mailbox Store using an online backup set and a backup client like NTBACKUP

or an offline restore using existing edb and stm files

Restoring an online backup set to a Recovery Storage Group

The steps to restore data to a Recovery Storage Group using an online backup

set are as follows:

1 Create a new Recovery Storage Group on any server in the same Administrative Group

2 Add the desired Mailbox Store(s) to the Recovery Storage Group

3 Before restoring from backup, dismount and delete any Mailbox Stores currently mounted in the Recovery Storage Group Remove any transaction log files (*.LOG) and checkpoint files (*.CHK) from the Recovery Storage Group to prevent them interfering with recovery

4 Restore a full backup set to the Recovery Storage Group server If you will not be restoring additional differential or incremental backups or adding additional log files for replay, you can set hard recovery to run

automatically In NTBACKUP this is done by checking the Last Backup

Set checkbox

5 If desired, restore incremental or differential transaction log backups Set

the Last Backup Set as appropriate

6 If desired, add additional transaction log files to be replayed to the Recovery Storage Group transaction log folder Verify that the sequence and

signatures of these log files match those in the backup set Use the

ESEUTIL /ml command to determine the signature of the log files

7 Verify that hard recovery has completed successfully by running the

ESEUTIL /mh command against the edb file The header should contain a

line called State: Clean Shutdown If Dirty Shutdown is displayed, then

hard recovery has not been initiated To initiate a hard recovery, use a command prompt and go to the folder containing the restore.env file and

issue the following command: ESEUTIL /cc

8 Verify that This database can be overwritten by a restore is checked and

then mount the Mailbox Store