Recovering log-structured filesystems from physical replicas
Systems, methods and apparatuses can present recovery of a log-structured file system. Embodiments can provide sending a request to a cloud store for backup data. The set of backup data received from the cloud store can comprise a set of data and metadata objects. The set of metadata objects can be read in a logical order. Each metadata object can be written from the set of data and metadata objects into block storage of the log-structured file system.
1. A computer-implemented method for recovering a log-structured file system, the method comprising:
sending a request to a cloud store for backup data, the backup data used to recover the log-structured file system;
receiving from the cloud store a set of backup data comprising a set of data and metadata objects;
determining that a valid recovery checkpoint does not exist in the backup data;
determining that all copies of metadata objects in the log-structured file system are corrupt;
creating a set of temporary metadata objects;
reading the set of temporary metadata objects in a logical; and
writing each metadata object from the set of data and temporary metadata objects into block storage of the log-structured file system.
2. The method of claim 1 , further comprising:
sorting the set of backup data; and
building the set of metadata objects using the logical block numbers of the data objects.
3. The method of claim 1 , further comprising periodically writing checkpoint information into the set of metadata objects.
4. The method of claim 1 , further comprising verifying the sanity of each metadata object written into block storage of the log-structured file system.
5. The method of claim 1 , wherein each of the metadata objects comprises multiple copies of metadata data.
6. A computer program product for recovering a log-structured file system, comprising a non-transitory computer readable medium having program instructions embodied therein for:
sending a request to a cloud store for backup data, the backup data used to recover the log-structured file system;
receiving from the cloud store a set of backup data comprising a set of data and metadata objects;
determining that a valid recovery checkpoint does not exist in the backup data;
determining that all copies of metadata objects in the log-structured file system are corrupt;
creating a set of temporary metadata objects;
reading the set of temporary metadata objects in a logical order; and
writing each metadata object from the set of data and temporary metadata objects into block storage of the log-structured file system.
7. The computer program product of claim 6 , further comprising:
sorting the set of backup data; and
building the set of metadata objects using the logical block numbers of the data objects.
8. The computer program product of claim 6 , further comprising periodically writing checkpoint information into the set of metadata objects.
9. The computer program product of claim 6 , further comprising verifying the sanity of each metadata object written into block storage of the log-structured file system.
10. The computer program product of claim 6 , wherein each of the metadata objects comprises multiple copies of metadata data.
11. A system for recovering a log-structured file system comprising a non-transitory computer readable medium and a processor configured to execute instructions comprising:
sending a request to a cloud store for backup data, the backup data used to recover the log-structured file system;
receiving from the cloud store a set of backup data comprising a set of data and metadata objects;
determining that there a valid recovery checkpoint does not exist in the backup data;
determining that all copies of metadata objects in the log-structured file system are corrupt;
creating a set of temporary metadata objects;
reading the set of temporary metadata objects in a logical order; and
writing each metadata object from the set of data and temporary metadata objects into block storage of the log-structured file system.
12. The system of claim 11 , further comprising:
sorting the set of backup data; and
building the set of metadata objects using the logical block numbers of the data objects.
13. The system of claim 11 , further comprising periodically writing checkpoint information into the set of metadata objects.
14. The system of claim 11 , further comprising verifying the sanity of each metadata object written into block storage of the log-structured file system.
15. The system of claim 11 , wherein each of the metadata objects comprises multiple copies of metadata data.