Showing posts with label Error 503 Service unavailable. Show all posts
Showing posts with label Error 503 Service unavailable. Show all posts

Monday, 14 August 2017

Migrating on-premise SQL Database to Windows Azure SQL Database

Migrating on-premise SQL Database to Windows Azure SQL Database

Migrating SQL database(s) from one server to another is one of the common tasks for SQL DBAs. There are several ways to migrate a SQL database(s). I have already covered how to migrate SQL DB on premise here. Today we will see how do we migrate an on-premise SQL Database to Azure SQL Database. Please follow the below step by step procedure to migrate your on-premise SQL Database to Azure-

1.       You need to login to the Source Server first. This is the Server where your Database, which needs to be migrated to Azure, resides. Login with your account and go to the Source database-> Click on Tasks-> Deploy Database to Windows Azure SQL Database.
Migrate your database to Windows azure SQL Database

2.       Upon clicking on Deploy Database to Windows Azure SQL Database you will be presented with the Deploy Database screen which will be an Introductory screen to provide you some information regarding the Wizard. Click Next

Migrating on-premise SQL Database to Windows Azure SQL Database

3.       Next screen will be Deployment Setting Screen where you need to provide the details for the target Server. Under the Specify Target Connection pane you will see a tab to enter Server connection. Click on the connect button which is situated at the right side of the server connection box. A new Connect to Server window will be popped up and there you should furnish the details of the target Server name and Authentication details. After entering the details click on connect.
Migrate your SQL Database to Windows Azure SQL Database, specify target server name
4.       Upon Clicking next, you will be presented with the below window where you can see the connected server name. you need to furnish some details like the new database name and other seeing details like Edition of windows Azure SQL Database, Maximum database size in GB and Service Objective. Here in our example I have selected “Standard” as the edition of Windows Azure SQL database and 250 GB is what I have mentioned as the Max size of the database and S2 as the Service Objective.

Migrate your SQL Database on Azure

Also, you need to specify a backpac file path in the Deployment Settings window. Once you are done with all these things, click next.

5.       Upon clicking next, a summary page will be shown which will have all the details about Source Server and database, target server and database and environment details.
Step by Step document for Migrating SQL Database to Azure

6.       Validate if all the above details are correct and proceed to click finish. Upon finishing the wizard you will see Operation complete message on the screen once all the operations such as Exporting database, Validating database, processing objects, importing database are complete.

Migrate SQL databases to Windows Azure

7.       To verify whether your newly migrated database has been migrated successfully or not you can go to Portal and check it. Login to with your credentials and see if the newly created database has been created under SQL Databases Pane. In our example, I logged into Azure portal and verified that the database with the name “test” has been created successfully under the SQL Databases pane.
Migrating on-premise SQL Database to Windows Azure SQL Database

Hence We have seen that Migrating an on-premise SQL server database to Windows Azure SQL Database is very easy and straight forward.

Saturday, 24 October 2015

Error 503 Service Unavailable

Error 503 Service Unavailable

A lot of our applications were hosted on IIS6 Server and as a part of upgrading all our applications we decided to migrate all the existing applications which are running on IIS6 should be migrated to IIS7 or later versions. We started doing the stuff from the scratch and things started going ahead pretty nicely. But then later on post migrating our applications from IIS6 to IIS7 we started getting the error "Error 503 Service Unavailable" upon opening the website. Post some research we found that this happens due to a setting related to the application pool identity It happens due to Start Automatically property set to false.

Error 503 Service Unavailable

Sometimes, this just happens when rapid fail back is enabled in the application pool. This feature of IIS 6.0 is available only when IIS is running in worker process isolation mode.When an application pool detects that too many worker processes assigned to it have become unhealthy in a given period of time, rapid-fail protection is initiated. The communication channel with the World Wide Web Publishing Service (WWW service) is dropped. The WWW service detects the loss of communication and initiates the appropriate actions, typically sending an error or warning to the event log and then restarting the worker process. The error can be suppressed by disabling the same.

Error 503 Service Unavailable

HTTP 503 errors are returned more often in IIS 6.0 than in earlier versions of IIS. Typically, the HTTP 503-Service Unavailable error is returned directly from HTTP.sys when there is a problem with getting the request up to the worker process. However, this error can occur for a variety of reasons, as listed in Table 11.11   HTTP 503 Errors from HTTP.sys.
HTTP 503 Errors from HTTP.sys
Reason StringText in HTTP.sys Error LogCause(s) of Error
Service unavailable.
IIS cannot start any new worker processes because of limited system resources or because starting a new worker process would exceed the DemandStartThresholdproperty.
Bandwidth throttling is enabled, but the filter addition fails.
The control channel or internal configuration group for the URL is inactive.
The send for a request that was serviced from the cache failed (typically under low memory conditions).
Too many users.
The connection limit for the site or server as a whole has been reached.
Application taken offline.
The application pool has been put into Rapid Fail Protection and has been disabled automatically.
Application request queue full.
The application pools request queue has been exceeded and the request cannot be queued.
Administrator has taken application offline.
The administrator has stopped the application pool.
Application automatically shut down due to administrator policy.
The application pool has been shut down because it exceeded its CPU usage limit.
Request timed out in app pool queue.
The application pool is too busy to handle the request. The request has, therefore, timed out in the queue and has been returned with a 503 error.

So We have seen, by following these simple steps we can get rid of Error 503 Service Unavailable error.