Manual talk:Backing up a wiki

Note: Some of the information in this page was adapted from Manual:Moving a wiki. robchurch | talk 20:59, 11 April 2007 (UTC)

"php dumpbackup.php --full" returns "DB connection error: Unknown error"
Peter Blaise asks:

I run:
 * C:\www\apache2\htdocs\mediawiki\maintenance>php dumpbackup.php --full
 * DB connection error: Unknown error

... and when I search the drive for new files, I see nothing's been created. How should an XML export / backup work? HELP, please!
 * -- Peter Blaise peterblaise 13:34, 20 June 2007 (UTC)


 * Learn to use a shell. You will notice that the dumpBackup.php script spits out XML. This XML should be saved into a file. The standard means of doing this is to redirect standard output to a file. On Windows (and also on POSIX-compliant shells), this is done using the > operator, e.g.


 * php dumpBackup.php --full > backup.xml


 * We expect our users to have at least a basic working knowledge of their computers. robchurch | talk 14:11, 21 June 2007 (UTC)


 * ...and geeks are expected to read carefully before bashing other users: Peters problem is not the output file, his problem is the DB connection error: Unknown error. Got the same under Kubuntu Feisty, seems something is wrong with the out-of-the-box installation. Cheers, 88.73.85.21 13:45, 21 July 2007 (UTC)

I'm getting the same error on an FC5 installation. Does anyone know the cause of this error. So far my Google searched haven't turned up any relevant information. Zeekec 20:32, 1 August 2007 (UTC)
 * I tried creating an AdminSettings.php file as suggested, but still get the same error. Zeekec 15:27, 2 August 2007 (UTC)

Similar problem with dumpBackup
Docduke says:
 * I have been using MediaWiki for about a year, and have about 20 MB of pages in 1.6.6. I have been backing it up regularly with mysqldump.  This computer is still running fine, but I would like to be able to move the data to another computer.  I installed 1.10.1 on the new computer, restored the data to mysql, and found that Table 'wikidb.objectcache' doesn't exist (localhost).  Rooting around some more, I found out about dumpBackup.  On the new computer, php dumpBackup.php --full > wikidump works.  On 1.6.6 it does not, and reports (Can't contact the database server: Unknown error).  Looking inside dumpBackup, I find, near the beginning:

require_once( 'command_line.inc' ); require_once( 'SpecialExport.php' ); require_once( 'maintenance/backup.inc' );
 * What does this do? Well, the PHP Manual says that it includes the files, and the link to "require" says that if it does not find them, it will fail.  However, looking around for these files, 'command_line.inc' and 'backup.inc' are in 'maintenance', but 'SpecialExport.php' is in 'includes'.  But how does php find the files?  'SpecialExport is in a different folder, and the prepended 'maintenance' edge on the third file suggests the program should be run from the root folder for the wiki.  In any case, the first and third are inconsistent.

It would be very helpful to readers if someone who has actually used dumpBackup can explain how it is supposed to be used, and what sets the environment so that files such as these can be found. The environment is very likely relevant, since the "keys" to the database come from LocalDefaults.
 * Docduke 2 August 2007 0147 GMT. P.S. The gremlins are working overtime tonight.  I logged into MediaWiki about a half hour ago, now it won't let me in.  I even had it send me a new password, and it won't let me in with that either!
 * Docduke 01:16, 2 August 2007 (UTC) [It let me in on a different computer]
 * Digging deeper ... In version 1.6.1, the "Can't contact the database server" message comes from line 1829 of includes/Database.php. My guess is that the "real" people adapt a copy of "index.php" to initialize the environment, then call dumpBackup from that environment in an automated backup script.  Either a copy of that script, or some indication of what is in it, would be greatly appreciated!
 * Docduke 02:48, 2 August 2007 (UTC)

I still have no idea how dumpBackup sets its environment, but I have found the solution to my problem, and probably that of the other folks who have reported backup failures. It is necessary to create an AdminSettings.php file at the wiki root from a copy of AdminSettings.sample, inserting a valid username, password pair for a DBuser with full privileges. Then dumpBackup runs when started in either the root folder or the "maintenance" folder, in version 1.6.6. It runs in 1.10.1 without an AdminSettings file because the LocalDefaults file has a username, password pair with administrator privileges. [Hint: I tried update.php. It failed, but the resulting error message said to check the AdminSettings file.]
 * Docduke 03:18, 2 August 2007 (UTC)

information needed on how to verify and restore a backup
Peter Blaise says:

Great overview, but so much more needed:
 * - how to verify our backup or export
 * - how to restore or import our data again

And we need specific, unambiguous, differentiating definitions of these words. Let me try:


 * "backup / restore":file copy, done from outside the program using the operating system utilities


 * "export / import":data copy, done inside the program using MediaWiki program interface utilities

... or something like that. Then we can clearly write specific steps (the "by doing what") for each way.

I agree that backing up everything is probably best, but, how does someone KNOW what's been customized and belongs to them, and what's standard and can be replaced from a fresh reinstall of the master software? Does any restore or reinstall routine intelligently preserve existing data? Or, do these process merely overwrite anything in their way? So, if I backup today, then crash tomorrow, and then restore yesterday's backup, and something is missing or it doesn't function properly, what should I do? I'd probably then reinstall from scratch to rebuild an empty MediaWiki structure. Then I'd try restoring from my backup again to fill in the supposedly completely rebuilt but empty structure. What if even that fails? What gets clobbered? How do I "know"?

Should I reinstall an empty MediaWiki and try to "import" data? What if I don't have a data "export", but I only have a file "backup" copy? How do I then reconfigure my customized choices? Do all my users come back with a restore or import?

So, it probably makes sense to preserve an mirror image off line and copy everything or one file at a time from there during troubleshooting if something's not working in the main system. My MediaWiki is small at the moment - ~500,000 words in ~4,500 sections, ALL files = ~120 MB, so making multiple copies to CD daily is acceptable, even ~5 backups to a CD will fit, total materials cost per year of ~$60 or less.

I suggest people try renaming directory structures to pull their main MediaWiki off line and TRY restoring their backup to a fresh directory structure to verify if their chosen backup routine works or not. If not, figure out why not before trusting our backups!


 * -- Peter Blaise peterblaise 11:21, 19 April 2007 (UTC)

--


 * I have moved the paragraph you added for now, as it's not quite correct:
 * See also Verifying a wiki backup and Restoring a wiki from a backup and Combining wikis from multiple backups. Note also that this page addresses backing up DATA only.  Your MediaWiki installation also probably includes much custom configuration in the form of changes to various supporting files that are as yet NOT incorporated into any database table, including CSS cascading style sheet files and PHP script files and JS Java script files.  You must backup and restore / re-integrate these as separate steps.  (Does someone want to write an extension to import and export all support files into supplemental database tables so everything is all in one place?)


 * The statement that the page is about data backup only is plain wrong - there's an extra section about backing up files; It could probably be more detailed, though. The only file that is "custom" by default is LocalSettings.php, and the uploaded files in the images directory of course.
 * Also, while red links are generally a good thing, they should "invite" people to write pages that actually make sense. First of all, those pages should be in the Manual namespace. "Verifying a wiki backup" isn't really possible, or rather, it's the same as Restoring a wiki from a backup (which is a page we should probably write soon). And Combining wikis from multiple backups probably doesn't make sense as a page of its own, and should be addressed in Restoring a wiki from a backup which should also explain what is overwritten when, or not.
 * There's also Manual:Moving a wiki, with which the contents of future pages should be coordinated.
 * Sticking everything into the database isn't really possible - the configuration must be outside, because it has to tell mediawiki how to access the database in the first place. Customized JS and CSS can go into the database (as MediaWiki:common.js and MediaWiki:common.css respectively), and that's the preferred way. Skins that need custom PHP code cannot reside in the database, program code needs to be in files (for technical as well as security reasons). Same for extensions. -- Duesentrieb ⇌ 11:32, 19 April 2007 (UTC)

Import config files, backup, verify, restore, automate
Peter Blaise says:


 * Why not auto-import text config files into the database?

Thanks, Duesentrieb. I see your points. Yes, there's mention of some support files, but I have dozens not mentioned! In my pushing for the maturation of MediaWiki, including it's support universe, I suggest that it could use a feature to automatically import copies of our custom config files into the main database even though it needs master copies of those files outside, in the operating system, in order to run properly. Your suggestion of manually creating copies as articles is interesting. How about automation, anyone?


 * Why not create an auto verify of backup?

I also see that you agree with me that there is no MediaWiki "verify" or "compare" option for backup or export, and as you say, so all we can do is try to restore or import and check it manually (against what, our memory of how the wiki behaved before?). Again, I'm pointing out a difference between "mature" applications we may have experienced before MediaWiki, and MediaWiki. My operating system backup application has a verify / compare feature after backup, MediaWiki has ... what?


 * Let's call items by their names, not shorthand.

Also, to reduce confusion and invite and enhance the quick success of newcomers, may I suggest sticking to a specific and complete nomenclature? You say you moved my comments to the "talk" pages, which I could not find. But, thankfully, I eventually found your link that brought me to the "discussion" page, which I'd already been looking at, and was already using. Why not call it the "discussion/talk" page? Thanks.
 * -- Peter Blaise peterblaise 18:02, 20 April 2007 (UTC)

--


 * The phrases "talk page" and "discussion page" are synonymous and interchangeable in MediaWiki wiki culture. robchurch | talk 00:54, 29 April 2007 (UTC)

--

Peter Blaise says:

So ... newbies, non-wiki culture people, are not invited to make the wiki their home? Rob, I'm suggesting that we recognize how offputting and success-inhibiting "jargon" is to newcomers. I suggest that we all foster growth by welcoming newcomers, and welcoming and recognizing criticism, not chiding them for their "not getting it, not fitting in". I'm suggesting that any Wiki is not owned by first comers, but is owned by anyone at any moment who is reading and offering their edits, their input at any time. I think this coincides with the intended Wiki "culture" more so than elitist jargon and belligerent exclusivity of first-comers against newbies.
 * "Why can't we all just get along?"
 * -- Rodney King

"Talk" and "discussion" ado not function as synonyms in that they are not interchangeable. Note this page's URL says "talk" yet this page's tab says "discussion". Try typing "discussion" into the URL and try looking for a "talk" tab. No can do. Is it so hard to say, "I moved your comment to the discussion/talk page" AND give a link, rather than presume others can figure out the ambiguity on their own, and then dismiss them when they suggest a way around getting lost?
 * -- Peter Blaise peterblaise 10:39, 1 May 2007 (UTC)

--


 * The problem is that internally, these pages are "talk" pages, and the namespace's english name has always been "talk" (and user_talk, etc). But the (english) text on the tab at the top of each page was at some point decided to be labeled "discussion" instead. This label can be changed by editing MediaWiki:Talk. Most other languages seem to use the equivalent of "Diskussion" on the label, and also as the Namespace name. Some languages may use something else entirely.
 * This is inconsistent and confusing, yes. But it's a fact that in the context of MediaWiki, "talk" and "discussion" are interchangable; Making "Discussion" an alias for the "Talk" namespace may be nice, but it would break backwards compatibility. This confusion isn't easy to resolve. It's better to explain it and live with it. -- Duesentrieb ⇌ 12:57, 1 May 2007 (UTC)

back up with phpmyadmin
If your host will not allow you to access such tools and you can only use phpmyadmin, or if this does not work for you, you might want to:
 * 1) export your full mysql wiki from phpmyadmin export functionality. Save the exported file locally.
 * 2) edit the exported file, and change the following if it applies for you:
 * 3) search and replace to change your tables prefixes (e.g., because prefixing is no more required on your new host)
 * 4) to work around the "latin1 in mysql > 4.1" character set problem, search and replace latin1 character set with utf8 one's. This might cause some strange behaviors afterwards because I'm not sure that media wiki won't be disturbed by the column encoding changing without warning. But apparently, for me, it works (and I found no other way to do it).
 * 5) * please note: as utf8 encoding take more space (three bytes per character) than latin1 (two, I think), some keys might become too large (my mysql installation does not allow keys > 1000 bytes). For these fields I didn't change the encoding (luckily these tables were empty at migration time). You can just do this by trial and error: phpmyadmin will warn you at import time if some key is too big.
 * 6) you might want to transform the utf8 to latin1 back with ALTER TABLE statements (phpmyadmin can do that for you). This will not revert the changes you just made as this time the contents will be re-encoded also.

Maybe this should be checked by some mediawiki expert and, if judged a good advice, integrated into the manual? I spent a full day searching for this workaround!