File Synchronization

Question

I am developing a website that has one production environment and DR environment(disaster recovering). In each environment i have three web servers and they need to have a shared storage to store some files like images. So i am thinking of have one SAN deployed for each environment. However, the two SAN in each environment has to be synchronized. In case production is done, users can access DR with same files.

So my question is is there a way to synchronized two SAN two way? No matter i write to any SAN, it will be synchronized to the other SAN.

Any other suggestions except using SAN is welcome for example using NFX.

Answer 1

Many SANs have block-level replication as a feature. This is going to be more efficient and reliable in almost all cases than file-level or application specific handled by the operating system.

Ultimately, it depends on what SAN you are using as this feature will vary from vendor to vendor, but any one worth its salt will have this as an option.

Answer 2

The problem is not the SAN, it is the filesystem ! You don't say on wich plateform you need that. On Linux, you can do : you can synchronize your SAN by using DRBD. But after, you need a clustered filesystem to handle the locks and collisions. You can look at OCFS2 or GFS, you will see that.