Systems and methods for write-ahead-log (wal) failover for transient disk unavailability

A system for failover between disks during transient unavailability, the system comprising:

• a processor;
• and
• a memory storing instructions that, when executed by the processor, configure the system to perform operations comprising:
• receiving a plurality of write requests configured to write data to each of one or more memory tables (memtables) stored by a second memory and one or more write-ahead-log (WAL) files;
• executing first write operations comprising execution of a first group of the plurality of write requests by writing a first part of the data to a first WAL file segment of a first WAL file of the one or more WAL files, the first write operations being directed to a primary disk and the first WAL file segment being stored by the primary disk;
• monitoring a primary disk health parameter of the first write operations;
• when the primary disk health parameter indicates transient unavailability of the primary disk, switching from the primary disk to a secondary disk and executing second write operations comprising execution of a second group of the plurality of write requests by writing a second part of the data to a second WAL file segment of a second WAL file of the one or more WAL files, the second write operations being directed to the secondary disk and the second WAL file segment being stored by the secondary disk;
• monitoring, in response to switching from the primary disk to the secondary disk, at least one of (i) at least one primary disk probe parameter of probe operations directed to the primary disk, or (ii) a secondary disk health parameter of the second write operations;
• and
• when at least one of (i) the at least one primary disk probe parameter indicates the transient unavailability of the primary disk is resolved, or (ii) the secondary disk health parameter indicates transient unavailability of the secondary disk, switching from the secondary disk to the primary disk and executing third write operations comprising execution of a third group of the plurality of write requests by writing a third part of the data to a third WAL file segment of a third WAL file of the one or more WAL files, the third write operations being directed to the primary disk and the third WAL file segment being stored by the primary disk.