Anyone know if there are performance or other issues, etc if there are more then 500-600 301 redirects in a single .htaccess file It is the only option I got for a short/medium term problem with a site move. Can't use wildcards for this one. Long term will eventually whittle them down to a dozen or so.
It will create problem & the page load time will be increased. http://stackoverflow.com/questions/4435482/is-it-okay-to-have-a-very-long-htaccess-file
Depends on what is more important, you will probably see a performance hit, but probably not worth worrying about in the long run, probably more important to make sure the redirects get indexed properly than worrying about the short term performance hit. It's a bit tedious but monitor the rankings of the redirects and remove them from htaccess as and when they get indexed.
Using htaccess in the first place is a huge performance hit. Apache's recommendation is to put stuff in the server config files so it is read only one time on server start versus on every request--and traversing up the directory hierarchy--as htaccess does. But htaccess is all that is available on shared hosting (which I assume you are using). And if you are on shared hosting, RewriteMap is not an option either. SOL. Perhaps you could test the time using the redirects and not and find out if there is a performance hit? When I had to do mass redirects, I had the old URL and the new URL in a database table. A quick SELECT query takes only a few thousandths of a second (I think about 6/1000ths back in the days of mechanical hard drives). Never would I have considered thousands of redirects in an htaccess file on shared hosting.
Thanks everyone! I will give it a go and test performance. Then reduce the lines to a bare minimum and test again. Will report back