Abstract The objective of the present study is to perform dynamic analysis on the small-scaled hydrodynamic bearings (HDB), which are nowadays in industry serve well as the candidates for supporting high-speed rotating spindles of data-storage drives; such as hard disc drives and optical disc derives. The analysis results are expected to serve for distilling design guidelines of the small HDBs with main goals of reaching required stiffnesses and simultaneously maintaining minimum oil leakage, the mostly-common design goals of small HDBs. To the aforementioned aims, herringbone-grooves and ferrofluids are particularly considered in this study. The analysis is started with building the mass flux equations of the bearing, which is followed by deriving the governing differential equation from the mass flow balance. Finally, the pressure of fluid film, stiffness, damping coefficients and critical speeds are calculated subsequently to investigate the effects of herringbone-grooves and ferrofluids on the dynamic characteristics of the HDBs.