Description Simon Streit 2023-01-06 16:29:24 CET

A customer has reported that they cannot create backups after
migrating their idmap backend to mdb [1]: 

root@primary0:~# /usr/sbin/univention-samba4-backup --days 15
Failed to open ./private/sam.ldb.d/CN=SCHEMA,CN=CONFIGURATION,DC=EXAMPLE,DC=COM.ldb
Error while backing up ./private/sam.ldb.d/CN=SCHEMA,CN=CONFIGURATION,DC=EXAMPLE,DC=COM.ld with tdbbackup - status 1

It is known that tdbbackup cannot create backups with mdb files.  An
alternative is to use mdb_copy.

This costumer was kind enough to provide a patch for a workaround to
this problem:

--- /usr/sbin/univention-samba4-backup        2022-11-21 10:23:01.000000000 +0100
+++ univention-samba4-backup        2022-12-27 14:06:25.388375524 +0100
@@ -129,7 +129,7 @@
 
 cd $FROMWHERE
 for d in $DIRS; do
-        relativedirname=`find . -type d -name "$d" -prune`
+        relativedirname=`find . -maxdepth 1 -type d -name "$d" -prune` # IMPORTANT: added -maxdepth 1 to avoid getting other dirs called "private" further down the tree, e.g. deep in the sysvol dir
         n=`echo $d | sed 's/\//_/g'`
         if [ "$d" = "private" ]; then
                 for db in tdb ldb; do
@@ -143,7 +143,12 @@
                                         tdbbackup $file
                                         Status=$?
                                         if [ $Status -ne 0 ]; then
-                                                terminate_on_error "Error while backing up $file with tdbbackup - status $Status"
+                                                echo "Error while backing up $file with tdbbackup - status $Status - will try mdb_copy in case MDB format is used" >&2
+                                                mdb_copy -c -n $file > $file.bak
+                                                Status=$?
+                                                if [ $Status -ne 0 ]; then
+                                                    terminate_on_error "Error while backing up $file with mdb_copy - status $Status"
+                                                fi
                                         fi
                                 fi
                         done


[1] https://help.univention.com/t/pre-update-checks-for-ucs-5-0-0-aborts-warning-about-a-very-large-samba-tdb-database/18014