Method and apparatus for mirroring data in a remote data storage system
AssigneeEMC Corporation
InventorYuval Ofek
Life of this patent
Estimating the term…
Abstract
A data processing network including a local system and a geographically remote system. Each of the local and remote systems includes a data storage facility. The remote data storage facility mirrors the local data storage facility. In a normal operating mode, the local and remote systems operate in near synchronism or in synchronism. In an alternate operating mode, writing operations at the local system immediately update the storage devices in the local data storage facility. Transfers of corresponding data to the remote data storage facility are made independently of and asynchronously with respect to the operation of the local system.
Claims11
A method for transferring data from a first data storage facility through an intersystem transfer path to a second, geographically remote data storage facility wherein each of the data storage facilities includes a data store for storing data in a retrievable form, wherein the first data storage facility includes interface means responsive to externally generated requests for a data transfer and means for determining the quantity of data to be transferred to the second-data storage facility and wherein said method normally transfers the data from the interface means to the first and second data storage facilities according to a normal operating mode, said method comprising the additional steps of:
- A) enabling an alternate operating mode and thereby disabling the normal operating mode, and
- B) thereafter responding to each request received at the interface means by:
- i) transferring the data from the interface means to the data store in the first data storage facility,
- ii) transferring the data from the first data storage facility to the second data storage facility;
- and
- iii) monitoring the quantity of data, said monitoring including:
- a) establishing a maximum quantity of data to be transferred to the second data storage facility,
- b) dynamically monitoring the quantity of data to be transferred to the second data storage facility, and
- c) reverting the operation to the normal operating mode when the monitored quantity exceeds the maximum quantity.
A control for effecting a transfer of data from a first data storage facility through an intersystem transfer path to a second, geographically remote data storage facility wherein each of the data storage facilities includes a data store for storing data in a retrievable form, wherein said first data storage facility includes interface means responsive to externally generated requests for a data transfer and a memory that identifies the quantity of data to be transferred to the second data storage facility and wherein said control normally transfers the data from the interface means to the first and second data stage facilities according to a normal operating mode, said control comprising;
- A) a mode controller that establishes an alternate operating mode and disables the normal operating mode, and
- B) means for transferring the data from the interface means to said data store in said first data storage facility during the alternate operating mode,
- C) means for transferring the data from said first data storage facility to the second data storage facility during the alternate operating mode,
- D) a monitor operable during the alternate operating mode including:
- i) a memory that stores a maximum quantity of data to be awaiting transfer to the second data storage facility, and
- ii) a dynamic monitor for determining a monitored quantity of data awaiting transfer to the second data storage facility, and
- E) means for reverting the operation to the normal operating mode when said dynamic monitor determines that the monitored quantity exceeds the maximum quantity.
A control for effecting a transfer of data from a first data storage facility through an intersystem transfer path to a second, geographically remote data storage facility wherein each of the data storage facilities includes a data store for storing data in a retrievable form, wherein said first data storage facility includes interface means responsive to externally generated requests for a data transfer and a memory that identifies the quantity of data to be transferred to the second data storage facility and transfers data in response to write requests received from the interface means and wherein said control normally transfers the data to the first and second data stage facilities according to a normal operating mode, said control comprising;
- A) a mode controller that establishes an alternate operating mode and disables the normal operating mode, and
- B) means for transferring the data from the interface means to said data store in said first data storage facility during the alternate operating mode,
- C) means for transferring the data from said first data storage facility to the second data storage facility during the alternate operating mode,
- D) a monitor operable during the alternate operating mode including:
- i) a memory for a maximum number of pending write requests for the second data storage facility,
- ii) a dynamic monitor that records the number of pending write requests for-transfer to the second data storage facility, said reverting means being enabled when the number of pending write requests exceeds the maximum number of pending write requests, and
- E) means for reverting the operation to the normal operating mode when the number of pending write requests exceeds the maximum number of pending write requests.
Dependencies are inferred from the claim text.