1. A method for use in managing data availability in storage systems, the method comprising: receiving a request to write new data to a disk of a plurality of disks of a data storage system, wherein the plurality of disks includes a row parity area and a diagonal parity area, wherein the row parity area includes row parity information and the diagonal parity area includes diagonal parity information, wherein up to two disks of the plurality of disks are having a problem; reconstructing old data of at least one failed disk in a memory of the data storage system; writing the reconstructed old data of the at least one failed disk to a parity area selected from the row and diagonal parity areas based on a configuration preference; and writing the new data to the parity area selected based on the configuration preference, wherein metadata of the parity area is updated to indicate that the parity area includes user data instead of parity information.