A: Best practices would definitely dictate that you create a second copy of your backup data for additional protection and reduced downtime. By doing so, you could then keep the original backup with an extra copy on site and a second copy off site. In the event of tape media failure, you could use your on-site copy (disk or tape) to restore, avoiding the delay of recalling media from the vault. In fact, some backup software, such as Tivoli Storage Manager, seamlessly switch to an on-site copy if it encounters read errors while accessing the original backup copy.

However, storage capacity and budgetary constraints often collide with best practices. This explains why few organizations implement dual backup copies. If a site has 10TB of production data, storage requirements for dual copies of backup data would grow to at least 30TB and potentially more, based on the company's data retention policies. An alternative is to restrict dual backup copies to systems with the tightest recovery-time objective.

--Pierre Dorion, storage architect, Mainland Information Systems Ltd.

Additional Questions:
	September 2004:	What should we do first: upgrade backup software and hardware or implement a SAN?
	August 2004:	What will happen to the Storage Management Initiative Specification (SMI-S) in 2004?
	July 2004:	Is there a cheaper alternative to Veritas VCS or Sun cluster for Sun on Sparc and x86 platforms?
	June 2004:	Can you tell me how implementing a network-attached storage (NAS) gateway could help with storage consolidation, as well as with direct-attached storage (DAS) issues?
	May 2004:	As an industry rule, how many storage administrators should be on staff per terabyte of data?
	Apr 2004:	How do you shred data stored on write once, read many (WORM) media?
	Mar 2004:	Why do you say that "bearings and the actuator arm mechanics used in the higher priced drives are rated for a more useful life than both IDE and ATA?"
	Feb 2004:	The theoretical maximum number of Fibre Channel Arbitrated Loop (FCAL) drives on a loop is 127, but what's a practical number?
	Jan 2004:	What are the variables to consider when determining how many host bus adapters (HBAs) are required per server?
	Dec 2003:	What kinds of tools can help me find files that are no longer used?
	Nov 2003:	Can you please explain what content-addressed storage (CAS) is, and what it's used for?
	Oct 2003:	What do you think of serverless backup?
	Sep 2003:	How do NAS blades in director-class switches work? Will they become popular?
	Aug 2003:	Which is best for consolidating storage in an SAP environment: SAN or NAS?
	Jul 2003:	I have 60% free space on 10,000 PCs. Can I consolidate it by mounting it as a volume and using a login script to map it to the desktops?
	Jun 2003:	Can you describe the steps that a single byte takes when going from memory to a spinning spindle and back again?
	May 2003:	What trends do you see in open-systems backup and recovery environments?
	Apr 2003:	What tools can we use to replicate domestic and overseas databases to one another?
	Mar 2003:	We're building an HSM solution to which we'll write 100GB+/month and store it for seven years. Do you think we should use CD, DVD or tape?
	Feb 2003:	I want to consolidate 10TB+ of files onto one system. Would you recommend products from EMC, NetApp or one based on Microsoft's SAK?
	Jan 2003:	I'm out of disk space on my Sun server running Oracle. Is NAS a good choice?
	Dec 2002:	File server cluster vs. network load balanced vs. DFS: What's the best method for file server HA?
	Nov 2002:	What are the pros and cons of storing user files on a RAID array with either ATA or SCSI drives?
	Oct 2002:	Can you do a LAN-free data transfer by giving an IP address to a FC adapter? Does it decrease the speed of data transfers to LAN speeds?
	Sep 2002:	What is the average amount of hosts for a centralized system to backup at one time?
	Aug 2002:	Why doesn't my mail client software create a lock for e-mail files if it's reading it off a NAS device? Which non-EMC NAS devices provide a gateway to connect to an EMC Symmetrix SAN?
	July 2002:	What does storage pooling mean? What do you think of it?
	May 2002:	What is the difference between a NAS gateway and a SAN appliance? Is tape still the best for archiving media files? Does it offer a lower TCO than disk?
	Apr 2002:	In terms of feed speed, what does that measurement refer to? Is it from the primary storage to the secondary storage? Does it stop at the write speed on the tape drive?
	Mar 2002:	How can you use solid-state disk (SSD) to accelerate SAN performance?