About AIM
Asynchronous mirroring is beneficial in environments where synchronous mirroring is not a viable solution due to distance and limited throughput. This is because during the synchronous mirroring process, I/O write acknowledgements are not returned to the requesting server until the data is received by both storage servers responsible for maintaining the mirrored virtual volumes. Over long distances, the latency involved would directly and negatively impact performance.
With asynchronous mirroring, it is understood that the throughput between the sites is limited, and therefore, I/O writes to the source virtual volume are acknowledged immediately. Replication of the data on the destination virtual volume is made as soon as possible, but lags behind.
The DataCore AIM (Asynchronous IP Mirroring) product, an optional licensed feature, allows you to asynchronously mirror disks (from laptops, personal computers, or application servers) to remote storage servers using standard Internet protocols ( IP) providing both data sharing and disaster recovery capabilities. Replication is performed at a block level; disk blocks that have been modified on the source are copied to the destination. We highly recommend using the DataCore Snapshot option with AIM, refer to Using Snapshot with AIM.
AIM can be used in a variety of configurations, ranging from simple unidirectional peer-to-peer servers— to a network of bidirectional servers, each with multiple source and destination volumes. Refer to AIM Configuration Models for more information.
What Can AIM Do for You?
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Mirror a local drive to a remote storage server
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Provide Disaster Recovery
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Restore a data disk if it fails
System Types
If licensed for AIM, during SANsymphony software installation, the storage server is automatically configured to act as both AIM Source or AIM Destination Servers. All storage servers acting as source or destination must be licensed to use AIM.
AIM Source Servers mirror the data received from application servers to one or more AIM Destination Servers.
AIM Destination Servers receive asynchronous mirrored data from one or more AIM Source Servers.
Source and Destination Servers can be storage servers with either the SANsymphony product or SANmelody product installed.
Transfer Mode Options
AIM provides two options for transferring data: File Transfer Protocol (FTP) which is best for data transfer over long distances (WAN), or Server Message Block (SMB) which uses common Windows File Sharing and is best for transfers on a LAN or Virtual Private Network (VPN).
Network Connectivity for Transfer Mode Options
TCP/IP connections are required between the source and destination servers.
(Instructions for data transfer configuration below is provided as part of the process in Getting Started with AIM.)
For AIM Destination Servers:
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For FTP mode, ensure installation of the FTP component ( IIS-FTP) of Microsoft’s Internet Information Server ( IIS). (Any compliant FTP package for Windows will also work.)
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Configure the FTP Home Directory as the top level of the AIM destination buffer with an FTP user account that has Write, Read, and Log Access/Log Visits selected.
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For SMB mode, allow incoming LAN connections from the AIM source server from a user defined in the Administrator group.
For AIM Source Servers:
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For FTP mode, allow out-going FTP connections from the AIM source server and incoming FTP connections from the AIM destination server.
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For SMB Mode, the source server must have the ability to access a defined network share on the destination server.
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Configure the DataCore AIM Source Service to log on as a user defined in the Administrator group and to also exist on the destination server.
AIM Buffers
If licensed for AIM, during SANsymphony installation, default source and destination buffers (shared as AimBuffer) are automatically created in the location of the SANsymphony files (default location is C:Program Files (x86)DataCore SoftwareSANsymphonyAIM). These buffers can be recreated and reconfigured to fit your needs. Refer to AIM Buffers for important information and best practices in configuring buffers.
To learn other AIM best practices, refer to the AIM Configuration section in Best Practices for Configuring and Using the SAN.
For a step-by-step guide to set up a basic AIM configuration, refer to Getting Started with AIM.
To add this feature to your license, contact your DataCore Sales Representative. (Note: AIM Client is a version of AIM that can be installed and configured on application servers and is not installed on storage servers.)