We have been experimenting with distributed file systems across multiple Linux instances connected to a shared block device. In our setup, the "disk" is not a legacy SAN or iSCSI. Instead it is a shared memory-semantic fabric that is being presented as a Linux block device.
We have been working with both GFS2 and OCFS2 to evaluate the suitability to work on our shared memory configuration. Right now we have gotten both GFS2 and OCFS2 to work with block driver but each file system still does block copies. Our goal is to extend mmap() of the file system(s) to allow true zero-copy load/store access directly to the memory fabric. We believe adding DAX support into the OCFS2 and/or GFS2 is an expedient path to use a block device that fronts our memory fabric with DAX. Based on the HW that OCFS2 and GFS2 were built for (iSCSI, FC, DRDB, etc) there probably has been no reason to implement DAX to date. The advent of various memory semantic fabrics (Gen-Z, NUMAlink, etc) is driving our interest in extending OCFS2 and/or GFS2 to take advantage of DAX. We have two platforms set up, one based on actual hardware and another based on VMs and are eager to begin deeper work. Has there been any discussion or interest in DAX support in OCFS2? Is there interest from the OCFS2 development community to see DAX support developed and put upstream? Has there been any discussion or interest in DAX support in GFS2? Is there interest from the GFS2 development community to see DAX support developed and put upstream? Regards, Bill
