Beginning with version 12, Adaptive Server initializes UNIX file system devices using the dsync option to ensure recovery. This could cause a performance impact to servers using file system devices for tempdb. If you require earlier behavior or performance characteristics, change the dsync setting using sp_deviceattr.
See the section New Unix File System Device Support in Chapter 6 of this manual. See also the sections on disk init and sp_deviceattr in the Reference Manual for more information.