End users and systems/storage integrators are cruising into the New Year with an unprecedented number of choices when it comes to disk drive/array interfaces and drive types: Fibre Channel, parallel SCSI, Serial Attached SCSI (SAS), parallel ATA, and Serial ATA (SATA). Choice is good, but it leads to some tough decisions that revolve around tradeoffs among performance, price, and reliability.
Which interfaces should you choose? The politically correct answer is that each interface has its place and there is a “right” choice for each application. Baloney. In almost all instances, more than one interface (or drive type) will fit the bill, and unless you want your server or storage subsystem vendor to dictate the solution you’ll have to weigh the tradeoffs.
To sort out these issues we invited some leading disk drive manufacturers to weigh in on the relative positioning of the various interfaces (see the Special Report on p. 22). The five opinions are characterized both by consensus and contention, but the more opinions you consider the more informed a decision you’ll make.
And if the existing options aren’t enough, you may have yet another option within the next year or so: FC-SATA. Similar in concept to SAS, which supports both SAS and SATA disk drives, FC-SATA systems would support both Fibre Channel and SATA drives. For more information, see p. 15.
Year of iSCSI?
Your choices don’t end at the disk drive level. IP SANs built on the iSCSI protocol continue to offer a viable alternative to Fibre Channel for cash-strapped IT organizations. Although 2005 didn’t live up to the “Year of iSCSI” billing (with iSCSI SAN revenues accounting for less than 2% of all SAN revenues), many end users have benefited from iSCSI, as illustrated in Michele Hope’s article, “Why users are embracing iSCSI SANs” (see p. 30), which presents a number of case studies. However, given the glacial pace of adoption of iSCSI (relative to expectations), a number of industry analysts are beginning to question whether iSCSI will ever climb out of its niche status to become a mainstream SAN alternative.
Last year, disk-to-disk backup and recovery was arguably the hottest trend in the storage industry. This year, however, users are going beyond the general concept of D2D backup and are investigating the various approaches. And as illustrated by two of our cover stories in this issue, virtual tape libraries (VTLs) and continuous data protection (CDP) are two of the most intriguing options. In our next issue we’ll delve deeper into both of these technologies.