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Dynamic Detection and Automatic Restoration of Dual Site Data Loss in Synchronous Remote Copy Environment

IP.com Disclosure Number: IPCOM000233961D
Publication Date: 2014-Jan-06
Document File: 8 page(s) / 96K

Publishing Venue

The IP.com Prior Art Database

Abstract

This invention builds daemons to automatically detect data loss and switch host access instantly and then restore lost data after disk array rebuilding finishes in synchronous remote copy environment. The daemons detect data loss during the array rebuilding and switch host access to the secondary volumes of the synchronous remote copy. If data loss happens against secondary volumes at the same time, the daemons also detect it. The daemons judge if the primary volumes and secondary volumes lose the same data and restore the available data. After the array in the primary machine has finished rebuilding, the daemons restore all of the primary lost data by copying from the secondary machine in a batch job. After the array in the secondary machine has finished rebuilding, the daemons restore all of the secondary lost data by copying from the primary machine in a batch job. The daemons also automatically switch host access back to the primary volumes by checking the status of the array rebuilding and data restoration. Based on the amount of data loss issues, this invention benefits a lot for customers to reduce the manual operation and service window and ensure the host application unaffected.

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Dynamic Detection and Automatic Restoration of Dual Site Data Loss in Synchronous Remote Copy Environment


1. BACKGROUND OF THE INVENTION


The data loss during the disk array rebuilding is a very common problem customers often meet with. That problem can be caused by different reasons, such as dual disk drive failures, RAID controller reset before rebuilding, FCAL loop empty before rebuilding, code bug, etc. The only restoration way is to copy the lost data from the backup. If the synchronous remote copy for the disaster recovery is configured, the secondary volumes of synchronous remote copy are the most commonly used to restore the lost data. And if the secondary volumes of synchronous remote copy also encounter data loss during the restoration of the lost data for the primary volumes, that makes the restoration complicated. Currently, restoring the data needs customer to follow the steps manually and put customer environment in the situation of data loss and single point of failure for a long time. Data loss needs a long service window to restore the data. Such kinds of issues have been encountered for many times by customers.


2. SUMMARY OF THE INVENTION


This invention builds daemons to automatically detect data loss and switch host access instantly and then restore lost data after disk array rebuilding finishes in synchronous remote copy environment. The daemons detect data loss during the array rebuilding and switch host access to the secondary volumes of the synchronous remote copy. If data loss happens against secondary volumes at the same time, the daemons also detect it. The daemons judge if the primary volumes and secondary volumes lose the same data and restore the available data. After the array in the primary machine has finished rebuilding, the daemons restore all of the primary lost data by copying from the secondary machine in a batch job. After the array in the secondary machine has finished rebuilding, the daemons restore all of the secondary lost data by copying from the primary machine in a batch job. The daemons also automatically switch host access back to the primary volumes by checking the status of the array rebuilding and data restoration. Based on the amount of data loss issues, this invention benefits a lot for customers to reduce the manual operation and service window and ensure the host application unaffected .


3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS


Daemon definition:
There are 2 daemons in each of primary and secondary machines of synchronous remote copy, DETECT_DMN and RESTORE_DMN. DETECT_DMN inspects the status of data loss and status of array and is also responsible to transmit the information of data loss to the secondary machine . RESTORE_DMN receives the information of data loss and controls the data restoration. Suffix is used to identify which machine the daemon exists in. DETECT_DMN_PRI and RESTORE_DMN_PRI are for primary machine and DETECT_DMN_SEC and RESTORE_DMN_SEC are for se...