While you are using WAN network you may face the problem of slow connections. It may cause various difficulties – i.e. during replication process. Open-E Data Storage Software – as a professional and versatile product – has been designed with solving this problem in mind.
Synchronous or asynchronous? This is the question.
There are two different cases. The first one is connected with block based volume replication. It is based on synchronous volume replication and can be used for NAS logical volumes. Such solution has two main benefits – data redundancy and maximum safety. Unfortunately, it can also generate high cost and must be used with WAN. Moreover, it may cause other problems – mainly due to slow connections. As an answer for WAN problems we can point to a second solution. Since it’s connected with data replication, it can work as an asynchronous process (only with NAS logical volume).
Asynchronous data replication over a WAN enables asynchronous file and folder copying from one storage system to another. With the asynchronous replication, a point-in-time snapshot copy of data on the source is made and copied to the target storage system. For maximum flexibility, you can run a data replication task in two directions: one system can be both the source and the destination at the same time, allowing cross data backups on several systems. Replication can be used in disaster recovery or for disk-to-disk backup.
In this case we may point to the benefits connected with the previously mentioned solutions – data redundancy and its maximum safety. Furthermore, we can also cut down inconveniences derived from slow connections. Unfortunately such solutions are also connected with high costs (while WAN network is used). There is also a necessity to use NAS logical volume.
It is all about your needs
So what is the best choice? It will always depend on needs. Synchronous volume replication will be almost always the best solution for LAN networks. And the reason is obvious – it is block based and is a continuous process. In the case of slow connections, while WAN network is used, asynchronous data replication will be better choice.