Flexible remote data mirroring

Abstract

Methods, systems, and configured storage media are provided for flexible data mirroring. In particular, the invention provides many-to-one data mirroring, including mirroring from local servers running the same or different operating systems and / or file systems at two or more geographically dispersed locations. The invention also provides one-to-many data mirroring, mirroring with or without a dedicated private telecommunications link, and mirroring with or without a dedicated server or another server at the destination(s) to assist the remote mirroring unit(s). In addition, the invention provides flexibility by permitting the use of various combinations of one or more external storage units and / or RAID units to hold mirrored data. Spoofing, SCSI and other bus emulations, and further tools and techniques are used in various embodiments of the invention.

Description

[0001] This application is a continuation of U.S. patent application Ser. No. 09 / 438,184, filed Nov. 11, 1999, entitled FLEXIBLE REMOTE DATE MIRRORING, now pending, which is herein incorporated by reference in it's entirety.FIELD OF THE INVENTION [0002] The present invention relates to the remote mirroring of digital data from a server or other computer in order to provide better fault tolerance and / or disaster recovery, and relates more particularly to tools and techniques for increasing the flexibility of remote data mirroring by permitting its use in a wider variety of network configurations than those previously used. TECHNICAL BACKGROUND OF THE INVENTION [0003] U.S. Pat. No. 5,537,533 describes tools and techniques for remote mirroring of digital data from a primary network server to a remote network server. A system according to that patent includes a primary data transfer unit with a primary server interface and a primary link interface, and a remote data transfer unit with a...

AI Technical Summary

Benefits of technology

[0018] Unlike some conventional mirroring approaches, the invention does not require a secondary server at the remote location in order to mirror data. A remote server may be used to test the integrity of mirrored data, or to replace a local server which becomes unavailable, but the remote server is not needed to maintain a complete copy of mirrored information in a bootable format at the remote location.

[0020] The local mirroring unit is non-invasive of the host operating system. It is not necessary to install on the mirrored local host an NLM or other software designed specifically for remote data mirroring. In particular, larger host volumes than before can be mirrored without degrading performance of the mirrored host, because the load on the host CPU is not substantially increased by mirroring according to the present invention. Putting the necessary processing in the local mirroring unit instead of in the host server also increases reliability and flexibility by making it possible to reconfigure or even reboot the local mirroring unit without interfering with host server processing.

Problems solved by technology

Nonetheless, these existing approaches have unnecessarily limited flexibility.

This required version of the Vinca product does not support any operating system / file system platform other than the Novell NetWare platform.

The hardware component of the necessary Vinca package also does not work with newer, faster servers and larger disk volumes.

Multiple servers at different locations cannot readily mirror to a single remote site.

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