Low capacity latency storage enclosure with expander
A storage enclosure includes a plurality of hard drive sub-boards, each configured to include a plurality of hard drives. Each hard drive sub-board is coupled to one or more expanders, via and interface unit, with a set of dual-pass shielded cables. The expander includes a plurality of chipsets coupled to a complex logic device. Each chipset may communicate with a different subset of hard drives with potentially different timing characteristics. The dual-pass shielded cables may be arranged to mitigate these differences. In addition, pin assignments associated with the cables may be set in order to further mitigate the timing differences.
1. A storage enclosure, comprising:
a first expander configured to receive input/output (I/O) data from a host computer system, wherein the first expander includes a plurality of chipsets;
a plurality of hard drives coupled to the first expander via a plurality of cables, wherein the plurality of cables routes the I/O data between the first expander and the plurality of hard drives to perform memory access operations; and
an interface unit coupled between the first expander and the plurality of hard drives and configured to:
receive the I/O data from a first chipset included in the first expander through a set of signal pins included in the interface unit;
determine a mapping between the set of signal pins and a set of signal wires included in the plurality of cables based on a signal pin assignment that is uniquely associated with the set of signal pins and the first chipset, wherein the signal pin assignment identifies only one path of a plurality of paths from the interface unit to a first hard drive included in the plurality of hard drives, wherein the only one path includes the set of signal wires, and
based on the mapping, transport the I/O data from the first expander to the first hard drive included in the plurality of hard drives via the set of signal wires.
2. The storage enclosure of claim 1 , wherein the plurality of hard drives includes:
a first subset of hard drives coupled to the interface unit via a first subset of cables included in the plurality of cables; and
a second subset of hard drives coupled to the interface unit via a second subset of cables included in the plurality of cables.
3. The storage enclosure of claim 2 , wherein the first subset of hard drives and the second subset of hard drives are connected to a first hard drive sub-board.
4. The storage enclosure of claim 2 , wherein the first subset of hard drives is coupled to a first hard drive sub-board, and the second subset of hard drives is coupled to a second hard drive sub-board.
5. The storage enclosure of claim 1 , wherein the first expander is further configured to transmit first I/O data to a first hard drive via a first cable included in the plurality of cables.
6. The storage enclosure of claim 1 , further comprising a second expander coupled to the interface unit and configured to:
receive the I/O data from the host computer system; and
transmit second I/O data to a second hard drive via a second cable included in the plurality of cables.
7. The storage enclosure of claim 6 , wherein the interface unit is further configured to perform a second signal remapping with respect to a second signal transmitted via the second cable to reduce a second latency associated with the second cable.
8. The storage enclosure of claim 1 , wherein the I/O data comprises a write command and corresponding write data.
9. The storage enclosure of claim 1 , wherein the I/O data comprises a read command, and at least one hard drive in the plurality of hard drives transmits read data in response to the read command.
10. The storage enclosure of claim 1 , wherein the mapping is generated based on simulation data.
11. The storage enclosure of claim 1 , wherein the mapping is generated based on a physical distance between the expander and the first hard drive.
12. A system, comprising:
a host computer configured to communicate input/output (I/O) data with a storage subsystem; and
the storage subsystem, comprising:
a first expander configured to receive input/output (I/O) data from a host computer system, wherein the first expander includes a plurality of chipsets;
a plurality of hard drives coupled to the first expander via a plurality of cables, wherein the plurality of cables routes the I/O data between the first expander and the plurality of hard drives to perform memory access operations; and
an interface unit coupled between the first expander and the plurality of hard drives and configured to:
receive the I/O data from a first chipset included in the first expander through a set of signal pins included in the interface unit;
determine a mapping between the set of signal pins and a set of signal wires included in the plurality of cables based on a signal pin assignment that is uniquely associated with the set of signal pins and the first chipset, wherein the signal pin assignment identifies only one path of a plurality of paths from the interface unit to a first hard drive included in the plurality of hard drives, wherein the only one path includes the set of signal wires, and
based on the mapping, transport the I/O data from the first expander to the first hard drive included in the plurality of hard drives via the set of signal wires.
13. The system of claim 12 , wherein the plurality of hard drives includes:
a first subset of hard drives coupled to the interface unit via a first subset of cables included in the plurality of cables; and
a second subset of hard drives coupled to the interface unit via a second subset of cables included in the plurality of cables.
14. The system of claim 13 , wherein the first subset of hard drives and the second subset of hard drives are connected to a first hard drive sub-board.
15. The system of claim 13 , wherein the first subset of hard drives is coupled to a first hard drive sub-board, and the second subset of hard drives is coupled to a second hard drive sub-board.
16. The system of claim 12 , further comprising a second expander coupled to the interface unit and configured to:
receive the I/O data from the host computer system; and
transmit second I/O data to the second hard drive via a second cable included in the plurality of cables,
wherein the interface unit is further configured to perform a second signal remapping with respect to a second signal transmitted via the second cable to reduce a second latency associated with the second cable.
17. The system of claim 12 , wherein the mapping is generated based on simulation data.
18. The system of claim 12 , wherein the mapping is generated based on a physical distance between the expander and the first hard drive.