System "big migration" Linux server migration method

Article title: System "big migration" Linux server migration method. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

Running a Windows NT Server is indeed brave or stupid because Microsoft no longer provides technical support for NT. With the surge in business volume and the continuous upgrading of applications, Windows 2000 has gradually become an old product and is about to end. If you work in a unit that is still running NT or 2000 (of course there are many such units in the world), you will have to migrate to another operating system anyway, for example, Linux.

You should first consider migrating some or all of the data center servers to Linux for many reasons. we will not discuss it here. However, if you decide to switch to an open-source system like Linux, some better methods are required.

Plan-select release version

First, before deciding to engage in a migration project, you must make an initial plan for your migration. it sounds a bit unconventional, but it will affect the success or failure of the migration. For example, you plan to only port Windows NT files, print servers, and domain controllers to Linux, is IT necessary to port the entire IT architecture (including Web and application servers and user desktops) to Linux in a longer term?

In the initial stage, it is critical to draw a clear blueprint. It should consist of three parts, namely, the server to be replaced, the tasks currently executed, and how Linux will complete these tasks.

The answer to these questions, coupled with the current IT staff's operating skills, helps determine which release version of Linux should be used. If you have extensive knowledge about a specific server-centric Linux release, this may affect your selection. Otherwise, you will select a release version with good vendor support.

Estimate migration costs and risks

The next step is to estimate the migration cost and time range. The best way is to break down the migration into as many manageable tasks as possible, and then estimate the time and cost for each task. The more detailed the decomposition and description tasks are, the more accurate the estimation may be. Of course, in the future test phase, these estimates will be generated to check and update the data.

Migrating NT files and printing servers to Samba in Linux is very easy, and saving the potential cost of the customer's access permission (CALs) is also huge. As Nick Lassonde, chief designer of Versora, a Linux migration consultancy in California, says a Samba server with proper configuration is usually much faster than a Windows NT or 2000 Server, the client does not feel the differences between the two systems.

Note the following risks with caution:

"The most common risk is ing security, because by default, most Linux versions only support POSIX security and incomplete access control tables (ACLs ), however, most modern file systems support ACLs, so this problem can be solved. ", This is a warning from Nick Lassonde.

You may want to configure your file server to verify the domain controller. there are some plug-ins to implement this. "Be familiar with Samba's Vampire command," Lassonde suggests. "It allows users to automatically migrate from the NT Domain controller to Samba ." In other words, it absorbs the essence of the NT Server, so that "Samba works as error-free as the NT4 server, and Samba4 has to go a long way to become an Active Directory domain controller, because it is not a very stable product."

For the Active Directory domain, setting a Linux-based selection scheme is feasible. the IBM software team recommends setting a Stack to include XAD running on Linux (from PADL ), LDAP and Kerberos 5.0 can be used as a feasible option for the Active Directory based on the Windows 2000 domain.

Migration Project

If your project contains more data centers that need to be migrated to Linux, the next step may be to move email and message services from Microsoft Exchange to software that can be accessed by traditional Microsoft desktop customers such as OpenXchange, or the IBM Lotus Domino system that the Outlook client can access.

The migration of Web and application servers is not that simple. you must ask the following questions:

What languages are used on the server (such as ASP, ASP. NET, and PHP )? Can these languages be used in Linux? If not, you need to find a third-party solution or convert the application to Linux.

What about other machines connected to the server? Which one is migrated first? For example, do you migrate the database to Linuxh first or stay in Windows?

What security options are required? Do you need to set up an SSL (encrypted socket protocol layer) connection on the new server? Is user authentication local or is it for intranet users in the domain?

The most obvious choice is to move from Microsoft's IIS Web server to Apache Web Server (according to Netcraft, it accounts for 65% of the Web server market) and Linux-based databases, which include DB2, Ingres, mySQL, Orcal, PostreSGL, etc.

The most difficult part of Linux migration is to Port applications. If application migration is part of your project, you can use a third-party solution. There are two examples in this regard: one is the ASP page running through Sun Java System Active Server Pages, and the other is the ASP using Visual Mainwin.. Net page, which provides a Windows library bound to the application and running on Linux.

Tools that transform applications from one environment to another are rarely worth using, Lassonde says, "in a large number of cases, the cost of converting an application from one language to another is almost the same as that of rewriting an application." He suggested leaving those applications on an ISS server and then using a neutral language (such as Java) to rewrite or convert them so that future changes can be implemented more easily.

Regardless of the scope of the Migration Project, remember, no matter how simple the project looks, no matter how well prepared you think, before you start (especially when this is your first migration attempt, it is almost guaranteed that the problem may suddenly occur. It is very likely that others have encountered the same problem before. Therefore, we must make full use of the support of public forums and consider hiring an experienced migration consultant. If he or she is a little outstanding, he or she may have encountered your problem before and can provide solutions to technical difficulties in a matter of minutes or hours. Otherwise, you may spend days or weeks to overcome these difficulties.