Efficient data read operation
In response to receiving a read metadata request from the host system for a data portion, the storage system may determine a status and location of the data portion, including determining whether the data portion is in a cache of the storage system. If the data portion is in the cache, the storage system may send a response that includes the data portion itself along with the status and location of the data portion. If the data portion is not in the cache, the storage system may send a response to the read metadata request that includes the status and location of the data portion, but not the data portion itself. The host system may be configured to determine whether the data portion has been returned with the metadata response, and if so, refrain from sending a separate data request, for example, to retrieve the data portion from cache.
1. A method comprising:
receiving on a host system a read request from a host application, the read request specifying to read a data portion from a data storage system;
in response to receiving the read request from the host application, the host system sending an instruction to the data storage system, the instruction specifying to read metadata for the data portion in association with the read request made by the host application;
receiving the instruction on the data storage system;
in response to receiving the instruction, determining whether the data portion is present in a cache of the data storage system; and
responsive to determining that the data portion is present in the cache, sending a response to the instruction that includes a location of the data portion in the cache and the data portion itself,
wherein the host system includes an operating system and a storage system interface directly connected to an internal fabric of the data storage system,
wherein the operating system communicates with the storage system interface over one or more peripheral device interconnects,
wherein the operating system receives the read request specifying a read operation, and, in response to receiving the read request, sends an IO communication specifying the read operation over one of the one or more peripheral device interconnects to the storage system interface, and
wherein the storage system interface sends the instruction in response to receiving the TO communication from the operating system.
2. The method of claim 1 , further comprising:
refraining from sending a separate read instruction to the cache to retrieve the data portion based on the data portion being included in the response to the instruction.
3. The method of claim 1 , wherein the instruction is sent from the host system to the global memory of the data storage system on the internal fabric independent of any director of the data storage system.
4. A system comprising:
one or more processors; and
a memory comprising code thereon that, when executed, performs a method comprising:
receiving on a host system a read request from a host application, the read request specifying to read a data portion from a data storage system,
in response to receiving the read request from the host application, the host system sending an instruction to the data storage system, the instruction specifying to read metadata for the data portion in association with the read request made by the host application,
receiving the instruction on the data storage system,
in response to receiving the instruction, determining whether the data portion is present in a cache of the data storage system, and
responsive to determining that the data portion is present in the cache, sending a response to the instruction that includes a location of the data portion in the cache and the data portion itself,
wherein the host system includes:
an operating system; and
a storage system interface directly connected to an internal fabric of the data storage system,
wherein the operating system communicates with the storage system interface over one or more peripheral device interconnects,
and wherein the method further includes:
the operating system receiving the read request specifying a read operation;
in response to receiving the read request, the operating system sending an TO communication specifying the read operation over one of the one or more peripheral device interconnects to the storage system interface; and
the storage system interface sending the instruction in response to receiving the IO communication from the operating system.
5. The system of claim 4 , wherein the method further includes: responsive to determining that the data portion is not present in the cache, sending a response to the instruction that includes a location of the data portion on a physical storage device of the data storage system, and does not include the data portion itself.
6. The system of claim 4 , wherein the method further includes:
refraining from sending a separate read instruction to the cache to retrieve the data portion based on the data portion being included in the response to the instruction.
7. The system of claim 4 , wherein the instruction is sent from the host system to the global memory of the storage system on the internal fabric independent of any director of the data storage system.
8. Non-transitory computer-readable media having software stored thereon, the software comprising:
executable code that receives on a host system a read request from a host application, the read request specifying to read a data portion from a data storage system;
executable code that, in response to receiving the read request from the host application, controls the host system sending an instruction to the data storage system, the instruction specifying to read metadata for the data portion in association with the read request made by the host application;
executable code that receives the instruction on the data storage system;
executable code that, in response to receiving the instruction, determines whether the data portion is present in a cache of the data storage system; and
executable code that, responsive to determining that the data portion is present in the cache, sends a response to the instruction that includes a location of the data portion in the cache and the data portion itself,
wherein the host system includes an operating system and a storage system interface directly connected to an internal fabric of the data storage system,
wherein the operating system communicates with the storage system interface over one or more peripheral device interconnects, and
wherein the software further comprises:
executable code that controls the operating system to receive the read request specifying a read operation, and, in response to receiving the read request, to send an TO communication specifying the read operation over one of the one or more peripheral device interconnects to the storage system interface; and
executable code that controls the storage system interface to send the instruction in response to receiving the IO communication from the operating system.
9. The non-transitory computer-readable media of claim 8 , wherein the software further comprises:
executable code that, responsive to determining that the data portion is not present in the cache, controls sending a response to the instruction that includes a location of the data portion on a physical storage device of the data storage system, and does not include the data portion itself.
10. The non-transitory computer-readable media of claim 8 , wherein the software further comprises:
executable code that refrains from sending a separate read instruction to the cache to retrieve the data portion based on the data portion being included in the response to the instruction.
11. The non-transitory computer-readable media of claim 8 , wherein the instruction is sent from the host system to the global memory of the data storage system on the internal fabric independent of any director of the data storage system.