A cluster network may manage the detection and handling of failures in a cluster of RAID arrays by detecting failures and reconfiguring the cluster. The non-planar parting line is comprised of a plurality of peaks and valleys that are offset from the dimple perimeters, as not to bisect any dimple edge. Another aspect of the present invention relates to use of said protecting groups in an orthogonal protecting group strategy for the synthesis of complex molecules that comprise a number of suitable functional groups. The exhaust ports are V-shaped slits. In order to accomplish the purpose, the present invention provides a wet friction material prepared by impregnating a base material including a fibrous substance with a thermosetting resin, and then thermally curing it, wherein the aspect ratio of the fibrous substance is 10 or higher, and the fibrous substance is contained in the base material in an amount of 60 to 75 weight %.