Database Mirroring failover

Hi,
I have configured mirroring, server A and server B, suppose if server A down, what are the action we need to tak bring up principal server.
Thanks in advance
Shashikala

Thank you. If we configured as safety with automatic failover. In this case mirror server will come online automaticaly if pricipl server down? or do we need to follow above steps to come nline.
Thanks
Shashikala
If witness is configured and principal is down and witness is able to form quorum with mirror automatic failover will happen. If quorum is not being formed anyhow for some reason no automatic failover will happen and then mnual failover will be required.
See various scenarios mentioned in below link (Database Mirroring Availability Scenarios)
Database mirroring in SQL server
Please mark this reply as answer if it solved your issue or vote as helpful if it helped so that other forum members can benefit from it.
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OCS 2007 R2 with SQL 2005 database mirroring failover?

We have OCS 2007 Enterprise Edition installed fine and with the databases mirrored to a backup server/location. I'm testing our environment for a potential disaster, including losing our primary SQL server (SQL 2005). I fail the databases over and update the backend pool to the backup SQL server name, but we cannot connect via Office Communicator and I see this error on the OCS server:
OCS User Services, error category 1006, event id 30962:
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driver={SQL Native Client};Trusted_Connection=yes;AutoTranslate=no;server=databkp;database=rtc;
Cause: Possible issues with back-end database.
Resolution:
Ensure the back-end is functioning correctly.
Can anyone shed some light on this SQL 515 error? Thanks in advance!
-Erik

We're having a similar issue but with error number 601. I've tried a million different things aside from restoring the database, which may be next. I tried editing the procedure and I *think* I edited the right lines 77 and 105 for me. Changed:
delete dbo.DbConfigDateTime
from @DbTime as t
where dbo.DbConfigDateTime.Name = t.ValueName
and t.StoredDbName = N'rtc'
and t.Value is null
to:
delete dbo.DbConfigDateTime
from @DbTime as t
where dbo.DbConfigDateTime.Name = t.ValueName
and t.StoredDbName = N'rtc'
and t.Value is not null
and
delete rtcdyn.dbo.DbConfigDateTime
from @DbTime as t
where rtcdyn.dbo.DbConfigDateTime.Name = t.ValueName
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from @DbTime as t
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and t.StoredDbName = N'rtcdyn'
and t.Value is not null
Not sure if that's where the modification is supposed to go. Any clarity here? Anyone else get a 601 error?

Database Mirroring Scenarios

Hi Everyone,
I am doing some test for database mirroring. I come with come with these two scenarios i unable to test out.
1) The principal database server disks full. In these case is the database mirroring failover will happen?
2) The principal database server and mirror database server disk full. In these case what will happen to database mirroring?

Hi,
No. Database mirroring endpoints use Transmission Control Protocol (TCP) to send and receive messages between the server instances participating database mirroring sessions. Automatic failover will occur if the principal
server has lost communication with the rest of the database mirroring configuration, while the mirror and witness retain quorum. If all server instances lose communication, however, and the witness and the mirror server later regain communication, automatic
failover does not occur.
See ‘Conditions required for an Automatic failover’ section in the below link:
http://technet.microsoft.com/en-us/library/ms189590(v=sql.105).aspx
Additional information:
Possible Failures During Database Mirroring
http://technet.microsoft.com/en-us/library/ms190913(v=sql.105).aspx
Thanks.
Tracy Cai
TechNet Community Support

Lack of support for FIM database mirroring

The official line is that database mirroring is not a supported architecture for the FIM deployment. I am not proposing using this, however I'd like to understand 1) What the issues really would be with a mirrored database deployment, 2) Will support
ever be added for this, and will it come in the form of SQL AlwaysOn?
Really appreciate help and input.
Rgds,
David

Database mirroring comes has two modes regarding transactions: synchronous or asynchronous.
Synchronous requires that the data be committed in both places before releasing the transaction. This has a big performance impact on the FIM Service database and to a lesser extent on the FIM Sync Database.
Asynchronous means that data isn't committed in both places at the same time, the mirror can fall behind and then in failover you could be behind. In order to have automatic failover with Mirroring you have to be able to modify the connection string to include
the failover partner or the client has to support getting that data at first logon. While you can modify the FIM database connection strings, it is not understood if FIM is using database clients that support mirroring. I believe it is. Even with asynchronous
you still have performance hit for copying every transaction to the mirror.
SQL Always On combines the best of mirroring and clustering to allow you to group databases together into an availability set, and then automatic failover the whole group to another server. It should be noted that Always On makes use of a similar underlying
mechanisms as mirroring to copy the data -- this is evident when you read that Always on also has an asynchronous and synchronous mode. You will most likely run into the same performance quandary.
Will the product group add support for it? My guess is that it depends on if they find a good way to address the performance issues.
David Lundell, Get your copy of FIM Best Practices Volume 1 http://blog.ilmbestpractices.com/2010/08/book-is-here-fim-best-practices-volume.html

Database Mirroring

If database in suspect mode what is going to be happen in mirroring? will it failover?

Yes I would say yes because suspect mode mostly likely occurs due to Hardware failure,
improper shutdown of the database server,
corruption of the database files, and of course unavailable database files and so on...
And as we all know in mirroring
unplanned downtime can be caused by hardware failures such as storage failure, by power outages, by human error, or by natural disasters, all of which can cause the production server as suspect mode or data center to be unavailable.
However if we talkling about Suspect_pages The principal recognizes a page read error, marks the page with an 829 error (restore pending), inserts a row into the suspect_pages
table in MSDB with the error status, and requests the page from the mirror. If the mirror is victorious in reading the page, it returns the page to the principal who applies it. After the page is repaired, the principal marks the page as restored — that is,
event_type =
5 in the suspect_pages table. Then any deferred transactions are resolved.
You can use this code SELECT
* FROM
sys.dm_db_mirroring_auto_page_repair
catalog view to displays corrupted pages in the data mirroring environment.
If the mirror fails, then the principal continues functioning, so the database continues to be available to the clients. The mirroring state is DISCONNECTED, and the principal
is running exposed in this case. You can use the sys.database_mirroring
catalog view to see the mirroring state on the principal server. Make sure you have plenty of disk space for the transaction log to grow on the principal and be sure to bring the mirror server online before you run out of disk space and your other option
will be using this code to break the database mirroring session ALTER DATABASE
<database_name> SET PARTNER OFF if you have to.
If the
witness is lost, the database mirroring session will continue functioning
without interruption, and the database will be available.
However If the
principal server is lost, the failover scenario
depends on the transaction safety (FULL or OFF) and whether a witness is present. if we talk about
FULL with a witness If Server A fails, then Server B will be the Principal but witness down Server B will not be able to Serve. so if we talk about
without a witness if the Principal fails the database is not accessible to client unless you don't have to go several
steps to make it available. Finally we talk about Principal with OFF (no witness) if the
principal is lost the database will be unavailable and then your option is to FORCE FAILOVER
I hope this will help and give you idea to make more research about it and overcome your problem. Good Luck

Database Mirroring - Witness Server

Hi,
Can I have a setup where both the Primary and the Mirror servers are running on SQL Server 2008 and Witness is running on SQL Server 2005? Somehere, I read that the witness can be of any edition, however the version has to match with the Primary and the
Mirror setup.
Could someone please confirm?
Also, if SQL Server 2008 Standard Edition supports automatic failover on Database Mirroring?
Thanks,

In the Microsoft SQL 2014 docs I see:
"We strongly recommend that the witness reside on a separate computer from the partners. Database mirroring partners are supported
only by SQL Server Standard edition and by SQL Server Enterprise edition.
Witnesses, in contrast, are also supported by SQL Server Workgroup and by SQL Server Express."
I figured I'd post this, since I ended up here looking for an answer to this question.

SQL Job failed on mirror failover

We have a SQL Server 2005 database mirroring configuration on two Windows Server 2008 R2 servers. There is a SQL Agent job that is triggered by a WMI Event Alert, using the query "SELECT * FROM DATABASE_MIRRORING_STATE_CHANGE WHERE State=8 AND
DatabaseName=[DB]".
The first step in the SQL job triggered by the alert is to execute a stored procedure in the database [DB] that has now just become principal on this server. On a recent automatic failover test, forced by rebooting the principal server, the mirror-turned-principal
fired the above alert, but the first job step failed with the error: "Unable to connect to SQL Server '(local)'. The step failed."
Subsequent job steps that executed other stored procedures in the same database were successful.
Some time line information:
9:50:34 SQL Log entry: "The mirrored database [DB] is changing roles from MIRROR to PRINCIPAL due to Auto Failover."
9:50:45 Alert fired
9:50:46 Job step 1 failed "Unable to connect to SQL Server '(local)'. The step failed."
9:51:32 Job step 2 "Changed database context to [DB]" (and the step succeeded)
This alert/SQL job combination has never failed in this manner on a similarly configured pair of mirror servers.
Can anyone shed light on why that first step would fail? Could the failover time be long enough that the database is not yet accessible? Yet the error refers to the server itself, not the database.
Since this is a production database, I have limited access to test the failover sequence, but any suggestions on what caused this job step to fail are welcome.

Hi,
I understand that it is the production environment, it is limited to take some testson it. Here are some comments:
1. When a job step fails, view the job history. Sometimesit will tell us more information aboutthe failure cause.
2. If you have a test environment, verify if the job are able to execute without the failover. I suspect it is failover that caused job step 1 to failed. In the test environment, we can change order of the job step and test the issue.
Regarding it is a production database, for quick and accurate answers to your questions, you can open a case with Microsoft, please contact Microsoft Customer Service.
http://support.microsoft.com/kb/295539
Thanks.
Tracy Cai
TechNet Community Support

Error in Starting Database Mirroring

Hai Everyone.. I have an issue in mirroring which i described below.
I am getting the above error when i click on "start mirroring" button. I turned off firewall in my antivirus.
And i also executed the below script in both my principal and mirror server. Because i created both the instances in my system only. And i am accessing those instances with windows authentication.
Go
GRANT CONNECT ON ENDPOINT:: EMP1_MIRRORING TO [DEVLAP5170\login];
Go
-- Thanks and Regards Srikar Reddy Gondesi, Trainee SQL Server Database Administrator Miracle Software systems, Inc.

Hi,
How’s everything going?
Also, see prerequisites for database mirroring:
For a mirroring session to be established, the partners and the witness, if any, must be running on the same version of SQL Server.
The two partners, that is the principal server and mirror server, must be running the same edition of SQL Server. The witness, if any, can run on any edition of SQL Server that supports database mirroring.
The database must use the full recovery model.
Verify that the mirror server has sufficient disk space for the mirror database.
When you are creating the mirror database on the mirror server, make sure that you restore the backup of the principal database specifying the same database name WITH NORECOVERY. Also, all log backups that were created after
that backup was taken must also be applied, again WITH NORECOVERY.
Helpful link:
Prerequisites, Restrictions, and Recommendations for Database Mirroring
http://msdn.microsoft.com/en-us/library/ms366349.aspx
Thanks.
Tracy Cai
TechNet Community Support

Alert: SQL Server Service Broker or Database Mirroring Transport stopped

Hi Team,
I got this error message even no one DB configured as mirroring ???
Alert: SQL Server Service Broker or Database Mirroring Transport stopped Priority: 0 Severity: 2 Resolution state: New
Alert description: The Database Mirroring protocol transport has stopped listening for connections.

Can you check the rule. By default the configurations are disabled state that is the reason you are getting the alert.
If it's not configured properly then you might need to override it
--Prashanth

Monitor SQL Database mirroring using powershell script

I am trying use the below powershell script to monitor SQL Database mirroring. The motive here is to determine if there are databases which are in "Disconnected" or "Suspended" mode.
I am running the script on the Principal Server:
$returnStateOK = 0
$returnStateWarning = 1
$returnStateCritical = 2
$returnStateUnknown = 3
$NagiosStatus = ""
# Load SMO extension
[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.Smo") | Out-Null;
# Servers to check
$sqlservers = @("$env:computername");
foreach($server in $sqlservers)
$srv = New-Object "Microsoft.SqlServer.Management.Smo.Server" $server;
# Get mirrored databases
$databases = $srv.Databases | Where-Object {$_.IsMirroringEnabled -eq $true -and $_.MirroringStatus -eq "Suspended" -or $_.MirroringStatus -eq "Synchronizing" -or $_.MirroringStatus -eq "Disconnected"
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if ($databases -ne $null)
$databases | Select-Object -Property Name, MirroringStatus | Format-Table -AutoSize;
exit $returnStateCritical
} Else {
Write-Host "All Databaes are Mirrored"
exit $returnStateOK
I have Suspended few databases for testing purpose but when I run the above script the output says "All Databaes are Mirrored"
If I make changes to $database and use it below i.e. I am changing the AND operator to OR after "$_.IsMirroringEnabled -eq $true"
$databases = $srv.Databases | Where-Object {$_.IsMirroringEnabled -eq $true -or $_.MirroringStatus -eq "Suspended" -or $_.MirroringStatus -eq "Synchronizing" -or $_.MirroringStatus
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Name
MirroringStatus
DB1
Synchronized
DB2
Synchronized
DB3 Synchronized
DB4
Suspended
DB5 Suspended
DB6
Suspended
DB7
Synchronized
DB8
Synchronized
I only want the databases which are Suspended or Disconnected to be listed.

I only want the databases which are Suspended or Disconnected to be listed.
Hi raul-133,
Based on your description, to list the databases which are Suspended or Disconnected ,I recommend you execute the following Transact-SQL statements in SQL Server firstly. If you can get the expected results from this query, then use the SQL Server query
in powershell script. For more details, please review this similar blog:
Monitor database mirroring.
Use master
go
select d.name, m.mirroring_state_desc
from sys.database_mirroring m,
sys.databases d
where m.database_id = d.database_id and (m.mirroring_state in (0,1))
For more details about mirroring state, you can review this article:
sys.database_mirroring (Transact-SQL).
Thanks,
Lydia Zhang

Mirror Database shows Recovery state in Database mirroring in sql 2012

Hi I am working on DBmirroring and have encountered problem of mirror database showing recovery state.
I tried to resolve issue by removing database mirroring from principal ,removing endpoints from both the nodes and
finally firing alter database db1 set partner off statement also.But when reconfigure dbmirroring on principal it does not allow
start dbmirroring and mirror database db1 comes in to recovery state from restoring stage.
srm_2010

ok in that case why it is not allowing me to configure db mirroring when I am trying from SSMS.It gives an error.tell me????
srm_2010
And what is the error ? If while configuring mirroring it fails for some reason you have to make sure the mirror database which has gone in recovery state needs to be brought in restoring state.
Please mark this reply as answer if it solved your issue or vote as helpful if it helped so that other forum members can benefit from it
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Oracle Database down /failover clause ?

hi
I am collecting the information regarding oracle database down / failover clouses , so all of you requested kindly send me your experience regarding Oracle database down/failover reason/clause.
thanks in advance
regards

Hi,
Are you looking for notes or scenarious.
If you are looking for some notes follow the below link:
http://pavandba.wordpress.com/category/dataguard/
Thanks,
Rafi.

Database link failover on RAC

Dear Friends.
Could you please provide me the information about implementation of Database links failover in RAC. (Oracle 10g RAC on linux)
I have created db links across the two RAC environments. Each RAC setup contains 2 nodes.
I have created DB link across the two RAC environemtns.
i.e I have created DB link between 1st node of Source RAC system to 1st node of Target RAC system.
If 1st node of Target RAC system is down, I need to setup in such way that the link should failover to node 2 of Target system.
I have tried all possible options of TAF. But I did not succeed. Is there anybody is implemented this type setup...?
How to setup tnsnames.ora on source DB to get this type of failover.
Thanks in Advance.
Best Regards
Kanumuri Raju

Oracle was kind enough to provide some configuration details in their docco. You may want to review this link:
http://download-east.oracle.com/docs/cd/B19306_01/network.102/b14212/advcfg.htm#sthref1275
The configuration needs to be performed in the TNSNAMES.ORA associated with the database initiating the link. If you want bi-directional TAF, you would need to update the TNSNAMES.ORA for 'both' databases.
I suggest you don't get your hopes up too high about the capability of TAF across DBLinks. I'm pretty sure you will not be able to get SELECT-based TAF. And I'm not absolutely sure which session rules will be used to determine the failover time.

Simple SQL Mirror Failover Setup?

Hello,
I would think this would be very simple however I can't find a single Adobe document with any information about it!
In ColdFusion 10 under the Data Sources / SQL Server there is a Connection String box...
From my hours of Google Searching it SEEMS like all you have to do is add: AlternateServers=(X.X.X.X:1433) to that box and SQL Mirroring failover should work and be automatic...is this correct?
If anyone has any documentation or experience with this I would greatly appreciate your input...it doesn't seem like this should be all that complicated...or unique...but all the info I find on this is either really old or not really pertaining to this simple setup.
FYI SQL Servers are Microsoft SQL 2008 R2 (I think SP2).
Thanks!

Seriously? Nothing? Bump!

Database Mirroring Idea

Hi Senseis
I was thinking about this concept and I want to know if someone else think the same idea before. As I say in other Thread, I will use database mirroring on top of MSCS to protect our systems. The mirror site will be in Miami and the primary in Cancun, Mexico. In the documentation says that the distance and bandwitch is essential for the succed of this configuration, so I will implement the high performance method. But (and is here where I want to know your opinions), if I recreate my production enviorement in the mirror site (I mean everything, disk distribution, SID, NSID, everything), apply the DB Mirroring and, in case of crash in my production site, just redirect the traffic to my mirror site... this will work?
Thanks for your help

I could imagine using a name in the SAPLogon to connect to the original system. If it fails you change one DNS entry to point to the other system and it should work.
But there are other things to consider:
- printers
- interfaces to other systems (BW)
- mounted file systems
Those need to be made aware too of the fact, that the systems IP changed.
Markus

Database Mirroring failover

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