SiSustainable

Site Migration Notes

- To migrate to a new server simply requires transferring the files to the new server and then changing the DNS records to point at the new servers IP.
- We do not need DNS access, but someone will have to change the DNS at some point.
- If not on our server, we would require SSH access the time of the transfer. The password can be changed after. Since the DNS is only changed after the migration, there is little security risk.

CMS
- To migrate to a new Content Management System usually requires rebuilding the site from scratch. Any element, such as colour, images and text, can be taken from the old site, but since nearly all the code must be rewritten it’s also the opportunity to improve or radically change the design.

Preserve old addresses

- A common problem in site migration is that the addresses of the new pages aren’t the same as the addresses of the old pages. So any link anywhere on the internet, in emails, or in documents, to the old pages will break. This is inconvenient for visitors but also search engines will assume you’ve deleted all your old pages and remove them from their search results, as well not consider all the old links to your website in evaluating it’s importance, and may even conclude you’ve plagiarized yourself (and so it can take a lot of time for your pages to reappear where they were).

ModRewrite
- The solution to pages that change location (in Apache Linux based servers) is found in a utility called ModRewrite, which can be used to point any address to any other address, in the case of site migration anyone going to any old addresses will automatically fall on the new page. Search engines will also be automatically directed to the new pages and simply note that the same page has changed location.

Not an html redirect
- ModRewrite works at the server level (before any page has been downloaded) and is completely different than an html redirect which will only activate after an html file has been downloaded. Html redirect is useful if the idea is to display one file after another (as it allows a time delay), but for site migration it requires all the old file structure being preserved causing disorganization, inconvenience for visitors, more design problems, and may have no effect on search engines.

Notes on ModRewrite
- ModRewrite is controlled from htaccess fils (a basic configuration file for the site), which can be placed at the root of the site as well as in subfolders. -ModRewrite can work on individual pages (or "request" for pages, since the old files are no longer there after the migration), or on types of files, such redirecting everything that was in one folder to a new folder, adding or taking away endings, etc. In brief ModRewrite is a space between the visitor and and the actual files, in which any file can be made to appear under any url (web address).
- ModRewrite can easily be used to create contradictions or never ending loops, in which case the server delivers error messages or stops working entirely. It is best to test on a local machine before uploading to a server.