kopano-core/ECtools/backup

kopano-backup is a MAPI-level backup/restore tool. it has three parts.

BACKUP
-kopano-backup can sync complete users/stores to disk, to be restored at a later time (-u, -S)
-it can sync multiple stores in parallel (for performance reasons, not folders; -w)
-it uses ICS to incrementally sync the respective MAPI items
-there is an option to sync only certain folders (-f, --recursive)
-it uses python-kopano to serialize items (item.dumps())
-the on-disk layout is basically a per-store (user) hierarchical directory tree,
with one directory for each MAPI folder
-for each MAPI folder, the following files are maintained:
'items': key-value store containing serialized version of every item in the folder
'index': key-value store containinfg subjects and dates for every item (for performance)
'state': ICS state
'path': folder path, for example 'Inbox/subfolder'
'meta': contains rules, acls, delegates for this folder
'folder': contains folder properties
-for each user/store, the properties are also stored globally as 'user'/'store'
-only a certain period may be backed up (-b, -e), though this may give weird effects when
combining with incremental backup
-there are certain options to skip e.g. attachments, junk mail, deleted items..

RESTORE
-kopano-backup --restore can restore complete users/stores back from disk
-the single argument given is the name of the directory which should be restored
-the user/account to restore to is taken from the directory name (-u can be used to specify otherwise)
-a 'restore root' can be specified, where to restore everything under (--restore-root, e.g. "dump/user3")
-there is an option to sync only certain folders (-f, --recursive)
-there is an option to restore only certain items, by sourcekey (--sourcekey; see STATS/INDEX below)
-it maintains original sourcekeys (PR_EC_BACKUP_SOURCE_KEY)
-if it detects a duplicate sourcekey, it will complain and not restore the respective item
-there is an option to specify a certain time period
-there are certain options to skip e.g. attachments, junk mail, deleted items..
-it should be mostly possible to restore on a different server, though this may result in minor data loss
-it is not parallelized at this point, but could be in the future
-when restoring items, they get a new sourcekey. but we'd like to check for duplicates, so we restore the
original sourcekey as PR_EC_BACKUP_SOURCEKEY

STATS/INDEX
-kopano-backup --stats gives a high-level summary of the contents of a backup directory
-kopano-backup --index shows all items contained in the backup directory, including folder path, subject and date
-the output format in both cases is CSV, which can be imported and inspected in e.g. LibreOffice
-there is an option to specify a certain time period
-to search for a specific subject, of course grep may be used.