Disk or tape? It has been a question asked in various forms for years. To be sure, it’s not entirely an either/or...
question, but with the newest generation of removable storage media, the choices are often made differently than in the past.
Removable storage media offers portability, along with the access speed of disk. But a bigger impact has probably been the products built by companies participating in the RDX Storage Alliance, which offers removable disk “cartridges” that work with special RDX docks aimed at data center users. Even the use of the term “cartridge” to describe a disk-in-a-box underscores the fact that the technology is aimed squarely at the traditional tape backup market. For example, Jesus Gonzalez, IT director at St. Baldrick’s Foundation, switched from tape cartridges to a removable disk system for backup (Tandberg Data’s RDX QuikStor) about two years ago, and there has been no looking back.
Gonzalez said there were two primary drivers for the transition: capacity and speed. “Sometimes you start with tape drive systems that meet your needs for a while but then they run out of capacity and often times you then have to buy a whole new tape drive system,” Gonzalez said. By contrast, he said, each “cartridge” in the RDX-type system has a capacity of a terabyte—ample for his present needs, he said. According to the manufacturer, the “street price” for an external Tandberg Data RDX dock ranges from $153 to $203 and the pricing for a 500 GB RDX cartridge ranges from $203 to $265.
Then there was the backup situation. With tape, sometimes backups were running seven to eight hours. “In an operation where people work late or run 24/7, it affects performance, servers run slow and everything is sluggish, that was always a problem for us,” he said. Furthermore, he noted, with tape, backups would often fail or “hang up” for reasons unknown.
“With disk, the backup windows are much shorter and we have found the reliability has been very good,” he said.
Removable disk storage a good fit for some SMBs
Other storage people have a similarly positive assessment of removable disk. Greg Allen at Active Technologies, LLC, an IT services firm, said removable disk is a great alternative for small- and medium-sized businesses (SMBs) that don’t have enough bandwidth to implement online or cloud backup, or who simply want to have ready access to of the most recent backup data.
On the other hand, Paul Capizzi, vice president of IT at SBLI USA Mutual Life Insurance Co., said removable disk storage hasn’t had a big impact on his environment. Smaller removable drives are issued on a case-by-case basis for individuals that need to move data and, of course, there are hot-swappable drives in the SAN array. But at present, Capizzi said there is a high level of comfort with tape as a known quantity. “We did recently retire some optical storage and move it to magnetic media but we are taking things in stages and also looking at cloud options for the future,” he said. Still, noted Capizzi, “Even if we move to the cloud I’m sure we will want to include periodic tape backups as a safety and comfort factor.”
A lot of the FUD being thrown around about tape in terms of environmental sensitivity to, for example, heat, applies equally to removable disk.
Greg Schulz, senior analyst, StorageIO Group
In truth, said StorageIO Group senior analyst Greg Schulz, removable disk and tape both have a place in backup and archiving. Disk has the benefit of more random access, which is helpful if you are searching for information. “The downside of disk is that it is several times more expensive; with the removable hard drive you pay a premium even above and beyond the higher price of disk capacity compared to similar tape, because you are paying for additional packaging,” he said. For example, the connector pins on removable disks are made for repeated insertions and the cases are more shock and static proof.
Schulz said the use case for removable disk varies across the market. As you go up market, it is more for portability. “Where in the past you might have used a CD or DVD for moving data from A to B or for archiving, now you might use portable disk,” he said. However, as you go down market there is a bigger upside play for archiving,” he added.
Removable disk also has a role in starting a relationship with a cloud provider. “If you are going to move several terabytes of data, how else do you get it there in a timely fashion if your network can’t support that?”
Schulz added a note of caution about removable disk reliability. “A lot of the FUD being thrown around about tape in terms of environmental sensitivity to, for example, heat, applies equally to removable disk,” he noted.
David G. Hill, principal and analyst at Mesabi Group LLC, said the choice of removable storage compared to other media is not that complicated. “Removable disk has the advantage that optical disk had with regard to random access read performance compared to the sequential access of tape and it shares the immutability and transportability capabilities with magnetic tape,” he said. However, Hill said, removable disk “does not have the scalability nor the robotics capabilities to move media around rapidly that a large tape library has,” and is therefore limited in its applicability at larger organizations.
Thus, he concluded, removable disk storage can be useful at “any organization that had a use for optical—this would tend to be SMBs—but there are possible opportunities in niches at larger companies,” he added.
Alan Earls is a frequent contributor to SearchDataBackup.