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Diffstat (limited to 'docs/recovery')
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diff --git a/docs/recovery b/docs/recovery new file mode 100644 index 0000000..80740c0 --- /dev/null +++ b/docs/recovery @@ -0,0 +1,67 @@ +Some tips what to do if (hopefully never), your database gets +corrupted: + +First there are three different databases used, residing in three +files in your --dbdir (normally db/): + +1) references.db +This file only contains the information which file in the pool/ +is needed by which target (i.e. which type/distribution/ +component/architecture quadruple). This is simply repairable by +deleting references.db and running "rereference". + +The current state of this database can be seen with "dumpreferences". +All references from some specific target can be removed with +"_removereferences". + +2) files.db and checksums.db +These files contain the information about which files in the pool/ dir +are known and what checksums they have. Files not in here will not be +deleted with "deleteunreferenced". Files being wrong here will not realized +(and thus not corrected even if told to be newly included) + +If both files exist, files.db is the canonical information and checksums.db +can be regenerated with a call to collectnewchecksums. +If only checksums.db is there, only that it used. (This means: if you +have called collectnewchecksums since you last used a version prior to 3.3 +with this repository, you can just delete files.db. But make sure to +never ever use a version prior to 3.0 on this repository after that.) + +To get this database in text form use "_listchecksums" without argument, +to add items manually pipe it into "_addchecksums". (Filenames +are handled as strings, so be careful). + +If the database is completely lost or broken, you can regain it by moving +files.db and checksums.db out of the way and running: +find $BASEDIR/pool -type f -printf "pool/%P\n" | reprepro -b $BASEDIR _detect +(or cd $BASEDIR && find pool -type f -print | reprepro -b . _detect) + +Also single files can be removed or added by "_forget" and "_detect". +(Again note filekeys will be handled as strings, so leading "./", double + slashes, "/./", symlinks and the like make them differ). + +4) packages.db +This file contains multiple databases, one for each target, containing +the chunks from the Packages or Sources files, indexed by package name. + +This one is the hardest to reconstruct. If you have still an uncorrupted +"dists/" directory around, (e.g. you just deleted db/ accidentally), +it can be reconstructed by moving your dists/ directory to some other place, +moving the packages.db file (if still existent) away, and set every distribution +in conf/distributions a "Update: localreadd" with localreadd in conf/updates like: +Name: localreadd +Suite: * +Method: copy:/<otherplace> + +with otherplace being the place you moved the dists/ directory too. + +If the packages database is corrupt, the described way can at least reconstruct +the Packages still landing in the Packages.gz and Sources.gz files. +If references.db is still accessible via dumpreferences, it can give hints +where the other files belong to. Otherwise removing references.db and calling +"rereference" and then "dumpunreferenced" will give you a list of files not +yet anywhere. + +Last but not least, there are also the "check" and "checkpool" commands, which +can give some hints about inconsistencies. (Check will also read files missing +from files.db+checksums.db if they are needed by packages but in the pool). |