DISTRIBUTED DATA PROTECTION: New Approaches to an Old Challenge

by Greg Schulz
April 1, 2005

Protecting and managing distributed data is a classic storage challenge for most environments. Distributed data is commonly perceived as being at remote locations, outside the data center, or not on a mainframe. Distributed storage includes network-based (LAN servers) storage file servers in a building, campus, or metropolitan area. Distributed storage supports a wide range of applications such as e-mail, database, e-commerce and more. With the proliferation of distributed and duplicated data, the complexity and cost to protect all this data is compounding proportionally. This article examines various techniques, including emerging trends and technologies, for accessing, protecting, and managing distributed data.

Distributed Data Protection Challenges

Network Attached Storage (NAS) over TCP/IP networks for file serving and sharing has become a popular choice for remote storage. NAS storage typically supports either (or both) Network File System (NFS) and Common Internet File System (CIFS). Some environments use both NFS and CIFS with some also using Novell Netware and Apple file sharing. NAS has been a popular choice for distributed data due to its ease of deployment and usage via dedicated file servers (also known as appliances or filers) and via general-purpose servers. Entry-level and Small-Medium-Size Business (SMB) storage subsystems attached to distributed servers also are popular for distributed storage either direct attached, or attached via a storage network interface. Storage networking interfaces and protocols include Internet SCSI (iSCSI) over Ethernet, NAS over IP-based networks, and Fibre Channel.

1. Potential threats to data and storage resources increase as more data is created and used outside traditional data center environments. The list of possible threats, and corresponding techniques to protect data, can be extensive. You should avoid simply treating all data the same. A tiered storage protection strategy aligns applications and server tiers to appropriate storage resources and protection categories. For example, some storage may be Redundant Arrays of Inexpensive Disks (RAID)-protected; other storage may use local RAID with a synchronous mirror copy offsite with Point-in-Time (PIT) copies for backups.  Infrequently accessed or old data may be archived to some other medium until needed. Other storage may be backed up regularly to an offline medium such as   disk or tape. Tiered storage is much more than simply deciding what type of disk drive to allocate to an application, based upon performance and space capacity. A challenge with distributed data, and storage in general, is that with snapshots, RAID, and improved reliability of disk drives, there can be a false sense of security. Data may not be backed up regularly, or, perhaps worse, it’s perceived to be protected, using a combination of RAID and PIT snapshots and isn’t actually being backed up.