Open-E DSS V6
The block access used in iSCSI is usually faster, more general, and more universal than file access. Block access supports virtually any application, including:
File access is more structured than block access. It supports ownerships, access restrictions, etc., and it is especially convenient if files need to be shared between multiple users or user groups with different access policies.
The main difference between block-based iSCSI and file-based NFS protocols is a fact that file-based NFS protocols include file locks. So even if a messaging layer detects the failure and a replicating layer has successfully synchronized both servers at the block-level, there is still a problem of locks opened by the clients. If the exported folder fails over from node one to node two, the files locks will remain on the server originally used to manage them. This causes an NFS problem, because clients start to transmit error messages but can no longer access needed files. To avoid this, the files locks also have to migrate to the new server.
If you own a full version of Open-E Data Storage Software V6, you can extend your system’s functionality by investing in NAS (NFS) Failover extension.