Data loss recovery in a secondary storage controller from a primary storage controller

Patent metadata

Field	Value
Publication number	US-11474707-B2
Application number	US-201615172774-A
Country	US
Kind code	B2
Filing date	Jun 3, 2016
Priority date	Jun 3, 2016
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

A secondary storage controller determines one or more tracks of one or more volumes in which data loss has occurred in the secondary storage controller. The secondary storage controller suspends a peer to peer remote copy operation between the secondary storage controller and a primary storage controller. Information on the one or more tracks of the one or more volumes in which the data loss has occurred is transmitted to the primary storage controller.

First claim

What is claimed is:

1. A method comprising,
in response to determining that a track in which data loss has occurred is a peer to peer remote copy secondary track in a secondary storage controller that is undergoing a synchronous peer to peer remote copy operation from a primary storage controller, creating a list of each peer to peer remote copy secondary track that has been affected by the data loss, and creating a lost track volume list that keeps track of all volumes that encountered data loss, and a range of tracks that needs to be recovered for the volumes from the primary storage controller;
dispatching a task to process the lost track volume list at a time that is a predetermined amount of time after a last data loss in a track has been observed or after no more data loss has been observed for at least the predetermined amount of time, wherein a timer is queued to process the lost track volume list for the predetermined amount of time, and for each additional track that is lost the timer is requeued once again for the predetermined amount of time to dispatch the task to process the lost track volume list once no data loss has been observed for at least the predetermined amount of time;
suspending, by the secondary storage controller, the synchronous peer to peer remote copy operation from the primary storage controller to the secondary storage controller, in response to determining via the tracks of one or more volumes in which the data loss has occurred in the secondary storage controller; and
transmitting information on the one or more tracks of the one or more volumes in which the data loss has occurred in the secondary storage controller, from the secondary storage controller to the primary storage controller, to avoid repeated interruptions of the primary storage controller from the secondary storage controller, and recovering the one or more tracks of the one or more volumes in which the data loss has occurred from the primary storage controller, wherein existing code to perform the synchronous peer to peer remote copy operation between the primary storage controller and the secondary storage controller remains unchanged in the primary storage controller, and wherein in response to an unsuspension of the synchronous peer to peer remote copy operation, for a volume performing:
sending a message to the primary storage controller indicating a volume number and a range of peer to peer remote copy secondary tracks that need to be restored, wherein the range of peer to peer remote copy secondary tracks that need to be restored is indicated by data structures indicating a start track and an end track; and
in response to receiving the message in the primary storage controller, updating an out of synchronization bit map for the volume with the range of peer to peer remote copy secondary tracks that need to be restored, wherein on a next primary resynchronization of data all peer to peer remote copy secondary tracks that are in the out of synchronization bit map for the volume are sent to the secondary storage controller, wherein in response to a process volume list task being dispatched once no data loss has been detected for the predetermined amount of time, cycling through a list and for volumes affected by data loss calling a copy service code component with a range of peer to peer remote copy secondary tracks comprising the start track and the end track that need to be restored from a remote copy of data, wherein a task sends a notification to a host coupled to the primary storage controller and the secondary storage controller that data has been restored in the secondary storage controller, and a suspend reason code indicates that the suspending of the synchronous peer to peer remote copy operation was performed because the data loss occurred on the secondary storage controller, and on the unsuspension of the synchronous peer to peer remote copy operation, recovery from the data loss will have taken place.

2. The method of claim 1 , the method further comprising:
accumulating over a period of time, by the secondary storage controller, the information on the one or more tracks of the one or more volumes in which the data loss has occurred, prior to transmitting of any part of the information to the primary storage controller.

3. The method of claim 1 , wherein the one or more tracks comprise a first track and a second track of a volume, the method further comprising:
in response to an unsuspension of the synchronous peer to peer remote copy operation, receiving by the secondary storage controller, data stored in the primary storage controller to restore data in a range of tracks starting from the first track to the second track of the volume of the secondary storage controller to recover from the data loss.

4. The method of claim 1 , wherein a data structure is updated in the primary storage controller to indicate that data of the one or more tracks of the one or more volumes are to be transmitted on continuation of the peer to peer remote copy operation to the secondary storage controller.

5. The method of claim 1 , the method further comprising:
determining, by a tertiary storage controller, a set of tracks of a volume in which data loss has occurred in the tertiary storage controller;
suspending, by the tertiary storage controller, another peer to peer remote copy operation between the tertiary storage controller and the secondary storage controller; and
transmitting, by the tertiary storage controller, information on the set of tracks of the volume in which the data loss has occurred to the secondary storage controller.

6. The method of claim 1 , wherein the secondary storage controller is a first secondary storage controller, wherein a multi-target peer to peer remote copy operation is in progress from the primary storage controller to the first secondary storage controller and a second secondary storage controller, the method further comprising:
determining, by the second secondary storage controller, a set of tracks of a volume in which data loss has occurred in the second secondary storage controller;
suspending, by the second secondary storage controller, another peer to peer remote copy operation between the second secondary storage controller and the primary storage controller; and
transmitting, by the second secondary storage controller, information on the set of tracks of the volume in which data loss has occurred to the primary storage controller.

7. A system comprising,
a memory; and
a processor coupled to the memory, wherein the processor performs operations, the operations comprising:
in response to determining that a track in which data loss has occurred is a peer to peer remote copy secondary track in a secondary storage controller that is undergoing a synchronous peer to peer remote copy operation from a primary storage controller, creating a list of each peer to peer remote copy secondary track that has been affected by the data loss, and creating a lost track volume list that keeps track of all volumes that encountered data loss, and a range of tracks that needs to be recovered for the volumes from the primary storage controller;
dispatching a task to process the lost track volume list at a time that is a predetermined amount of time after a last data loss in a track has been observed or after no more data loss has been observed for at least the predetermined amount of time, wherein a timer is queued to process the lost track volume list for the predetermined amount of time, and for each additional track that is lost the timer is requeued once again for the predetermined amount of time to dispatch the task to process the lost track volume list once no data loss has been observed for at least the predetermined amount of time;
suspending, by th

Assignees

• IBM

Inventors

• Carson Matthew D
• Mellgren Carol S
• Nielsen Karl A
• Sanchez Matthew
• Sorenson Todd C

Classifications

• G06F3/0689

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/065

  Replication mechanisms · CPC title

• G06F11/1662

  the resynchronized component or unit being a persistent storage device (re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008) · CPC title

• G06F3/0619 Primary

  in relation to data integrity, e.g. data losses, bit errors · CPC title

• G06F11/14

  Error detection or correction of the data by redundancy in operations (error detection or correction of the data by redundancy in hardware G06F11/16) · CPC title