A method comprising: a storage server (110, 310, 400) receiving a write request to store data blocks (175, 360, 435, 445), wherein the storage server (110, 310, 400) comprises a plurality of nonvolatile memory devices (120, 320, 410, 420) that cache data blocks (175, 360, 435, 445) stored on primary storage (160, 305, 405), wherein the data blocks (175, 360, 435, 445) reside in a first nonvolatile memory device of the plurality of nonvolatile memory devices (120, 320, 410, 420), wherein the storage server (110, 310, 400) maintains a cache index (150, 490) of data blocks (175, 360, 435, 445) that reside in the plurality of nonvolatile memory devices (120, 320, 410, 420); characterized by: detecting, in response to receiving the write request, that the first nonvolatile memory device is saturated or otherwise temporarily unavailable; and based on said detecting that the first nonvolatile memory device is saturated or otherwise temporarily unavailable, the storage server (110, 310, 400): rerouting the write request to a second nonvolatile memory device of the plurality of nonvolatile memory devices (120, 320, 410, 420); and storing an identifier (155, 450, 460) of the second nonvolatile memory device in the cache index (150, 490). a storage server (110, 310, 400) receiving a write request to store data blocks (175, 360, 435, 445), wherein the storage server (110, 310, 400) comprises a plurality of nonvolatile memory devices (120, 320, 410, 420) that cache data blocks (175, 360, 435, 445) stored on primary storage (160, 305, 405), wherein the data blocks (175, 360, 435, 445) reside in a first nonvolatile memory device of the plurality of nonvolatile memory devices (120, 320, 410, 420), wherein the storage server (110, 310, 400) maintains a cache index (150, 490) of data blocks (175, 360, 435, 445) that reside in the plurality of nonvolatile memory devices (120, 320, 410, 420); characterized by: detecting, in response to receiving the write request, that the first nonvolatile memory device is saturated or otherwise temporarily unavailable; and based on said detecting that the first nonvolatile memory device is saturated or otherwise temporarily unavailable, the storage server (110, 310, 400): rerouting the write request to a second nonvolatile memory device of the plurality of nonvolatile memory devices (120, 320, 410, 420); and storing an identifier (155, 450, 460) of the second nonvolatile memory device in the cache index (150, 490). detecting, in response to receiving the write request, that the first nonvolatile memory device is saturated or otherwise temporarily unavailable; and based on said detecting that the first nonvolatile memory device is saturated or otherwise temporarily unavailable, the storage server (110, 310, 400): rerouting the write request to a second nonvolatile memory device of the plurality of nonvolatile memory devices (120, 320, 410, 420); and storing an identifier (155, 450, 460) of the second nonvolatile memory device in the cache index (150, 490). rerouting the write request to a second nonvolatile memory device of the plurality of nonvolatile memory devices (120, 320, 410, 420); and storing an identifier (155, 450, 460) of the second nonvolatile memory device in the cache index (150, 490).