DirectoryStorage Disaster Recovery

Help! My hard disk ate my storage! What do I do?

The right option is to switch to a replica or restore a backup.

You do have one, don't you?

If not, read on.

DirectoryStorage Salvage

Please note that this process has never been tested by the DirectoryStorage developers (and hopefully never will be).

After performing any recovery necessary on the disk or filesystem, you may want to try:

1. If the directory structure is lost and you have files in lost+found, use the dumpdsf.py tool on each of them. The correct file name can can be reconstructed from redundant information in the file header.
2. DirectoryStorage should carry on like FileStorage, accesses within your application may raise a POSKeyError exception for missing files or DirectoryStorageError if the md5 checksums are bad. Recovery from there could be the same as FileStorage; remove the bad objects from within the application.
3. The checkds.py tool can be used to find the files with bad md5 checksums. You may want to inspect them, or remove them if POSKeyError is easier to repair than DirectoryStorageError.
4. If you are if you are an expert in the storage directory layout you may consider patching missing objects by copying individual files from elsewhere in the storage, or from a slightly-out-of-date backup.