Achieve 100% Uptime by Alternate Indexes
Achieve 100% Uptime by use of Alternate Indexes
Large indexes can have significant downtime during reindexing. If you have and are willing to double the disk usage, you can completely eliminate downtime by creating alternate indexes.
The method is simple: just create two separate archives, both indexing the same set of data. Adjust your crontab to stagger the times of reindexing so that the indexing times do not overlap (you will have to test and see how long each actually takes to index). Recall that the file wgreindex is the script in the archive directory that is run from crontab to reindex.
Then, edit your search form and replace the <input name=ID value=[N]> tag with the following set of tags:
where [N] and [M] represent the archive id's for the two identical (except for reindex times) archives. You can actually have more than two alternate archives to search, if that is desireable for some reason.
<INPUT TYPE=HIDDEN NAME="ALTERNATE" VALUE="Y">
<input type=HIDDEN NAME="ARCHID_1" value="[N]">
<input type=HIDDEN NAME="ARCHID_2" value="[M]">
This technique is in use on the high-traffic bTucson.com site.