SELECTING STORAGE CLUSTERS TO USE TO ACCESS STORAGE
Provided are a method, system and program for selecting storage clusters to use to access storage. Input/Output (I/O) requests are transferred to a first storage cluster over a network to access storage. The storage may be additionally accessed via a second storage cluster over the network and both the first and second storage clusters are capable of accessing the storage. An unavailability of a first storage cluster is detected when the second storage cluster is available. A request is transmitted to hosts over the network to use the second storage cluster to access the storage. Hosts receiving the transmitted request send I/O requests to the storage via the second storage cluster if the second storage cluster is available.
1 . An article of manufacture comprising a computer readable storage medium including code capable of causing operations to be performed with respect to a first storage cluster, second storage cluster, and hosts over a network, wherein a storage may be accessed via the first and second storage clusters, and wherein the code is implemented in one of the hosts to perform operations, the operations comprising:
transferring input/output (I/O) requests to the first storage cluster over the network to access the storage;
detecting an unavailability of the first storage cluster when the second storage cluster is available; and
transmitting a request to the hosts over the network to use the second storage cluster to access the storage, wherein the hosts receiving the transmitted request send I/O requests to the storage via the second storage cluster.
2 . The article of manufacture of claim 1 , wherein the operations further comprise:
sending messages to hosts over the network requesting permission to switch from using the first storage cluster to the second storage cluster;
receiving responses from the hosts to the messages indicating whether the hosts provide permission to switch from the first to the second storage cluster; and
determining from the received responses whether to switch from using the first to the second storage cluster to send I/O requests to the storage.
3 . The article of manufacture of claim 2 , wherein the selection is not made to use the second storage cluster and the requests are not transmitted to the hosts if the determination is made to not switch from using the first storage cluster to using the second storage cluster based on the received responses.
4 . The article of manufacture of claim 2 , wherein the determination is made to switch from using the first storage cluster to the second storage cluster if all hosts receiving the message respond indicating permission to switch from the first storage cluster to the second storage cluster.
5 . The article of manufacture of claim 2 , wherein the operations further comprise:
failing I/O requests to the storage in response to determining not to switch from using the first storage cluster to using the second storage cluster.
6 . A system in communication with hosts, a first storage cluster, and a second storage cluster over a network, wherein a storage may be accessed through the first and second storage clusters, wherein the system comprises one of the hosts external to the first and second storage clusters, comprising:
a processor; and
a computer readable storage medium including code executed by the processor to perform operations, the operations comprising:
transferring input/output (I/O) requests to the first storage cluster over the network to access the storage;
detecting an unavailability of the first storage cluster when the second storage cluster is available; and
transmitting a request to the hosts over the network to use the second storage cluster to access the storage, wherein the hosts receiving the transmitted request send I/O requests to the storage via the second storage cluster.
7 . The system of claim 6 , wherein the operations further comprise:
sending messages to the hosts over the network requesting permission to switch from using the first storage cluster to the second storage cluster;
receiving responses from the hosts to the messages indicating whether the hosts provide permission to switch from the first to the second storage cluster; and
determining from the received responses whether to switch from using the first to the second storage cluster to send I/O requests to the storage.
8 . The system of claim 7 , wherein selection is not made to use the second storage cluster and the requests are not transmitted to the hosts if the determination is made to not switch from using the first storage cluster to using the second storage cluster based on the received responses.
9 . The system of claim 7 , wherein the operations further comprise:
failing I/O requests to the storage in response to determining not to switch from using the first storage cluster to using the second storage cluster.