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LTO-5 Tape Library Upgrade? Update Your Backup Server First

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We’re talking about Tape? Really?

Yes, believe it or not we are talking about tape — tape drives, autoloaders and libraries. While many people have adopted spinning disk in one form or another for their primary backups needs, tape remains the best choice for long-term archival and is still an economical choice for smaller requirements. 

For example, consider the portability of an LTO-5 tape cartridge: It can hold up to 3-TB on a single tape cartridge (perhaps more using software de-duplication) measuring 4.1 x 4.0 x 0.8 inches, which you can probably fit in your pocket! Furthermore, LTO tape meets long-term regulatory compliance requirements and has a shelf life of 30 years. Also, a tape cartridge resting on a shelf uses no electricity and requires no cooling.  In short, tape provides practical, inexpensive long-term storage.

LTO-5 (Linear Tape Open) Ultrium

Even though we are firmly in the age of disk backup, there are still quite a few tape formats available: DAT/DDS, SLR, VXA, DLT/SDLT and LTO. However, it seems clear that LTO has the lead in longevity and market dominance. The roadmap for LTO is one reason; while other formats are nearing the end of their lifecycle because of engineering limitations, LTO still has further advancements planned. As you can see in the image below, while LTO-5 is the current model, the roadmap indicates improvements out to LTO-8.

LTO Speed  

The LTO-5 specification is 280 MB/s at 2:1 compression which is 40 MB/s or 15% faster than LTO-4 and 120 MB/s faster than LTO-3. In fact, LTO-5 is so fast that the preferred connectivity is either SAS or Fibre-Channel and therefore traditional SCSI-equipped models are few. An update over LTO-4, the LTO-5 Fibre-Channel interface supports the newer 8-Gb Fibre-Channel network specification.

Backup Server Support Capabilities

We often see companies invest in a new tape library and cable it up to a backup server that has worked well for the past five years only to be disappointed by the apparent lack of improved performance. Guess what? That new tape library is not the problem; the problem is the old backup server. This situation is analogous to installing a small lawnmower engine into an otherwise high-performance sports car and expecting stellar results. 

To ensure compatibility with tape library upgrades, it is of paramount importance to consider the complete configuration of the server, including processor, memory and the I/O interfaces. The server must be able to pull the data from the sources and then feed the data to the tape device as fast as the tape device can accept it. Otherwise the tape drive will either lay down blank space on the tape cartridge or shoe-shine back and forth as it waits for the data stream to catch up. The tape actually moves past the heads at several miles per hour!

Backup Server Recommendations for Tape Library Upgrades

So, how can you ensure a successful tape library upgrade? First, your backup server should be a dedicated, physical machine — not a virtual server. This is because it will have a physical interface card (SAS, Fibre-Channel or SCSI) that is connected directly to the tape drive, autoloader or library.

However, if you have a SAN (Storage Area Network) and have your tape library is cabled directly to your SAN switch, your backup server might be running upon a virtual machine.

Assuming that your backup server is a physical machine, start with any guidelines or recommendations provided by your backup software vendor. After that, use the following advice:

• Your backup server should be a modern, dedicated 64-bit machine unencumbered with other tasks or applications.
• A single, 64-bit quad-core processor should be sufficient. Alternatively, use a dual-processor capable server, then monitor the server during use to determine if it is processor bound and install the second processor if required.
• Install 16-GB of memory as a minimum. Memory is relatively inexpensive these days and this is not the area in which to be conservative.
• If your backup software supports it, use the 64-bit version of the operating system.
• Separate regular LAN communications traffic from your backup traffic. You can do this by installing extra Gigabit LAN adapter cards in all of the servers that are to be backed up and in your dedicated backup server as well. Then, use a separate Gigabit Ethernet switch or a VLAN to create a dedicated backup network, thus achieving the desired result of segregating your traffic.  This is illustrated in the following diagram.

Your Thoughts?

Have you recently updated your tape library? What process did you go through to ensure a successful upgrade?

Perry Szarkais the Data Center Strategic Business Unit leader

Perry Szarka is a Solution Consultant at MCPc with expertise in data storage and network infrastructure. He works closely with clients to understand their business objectives and discover solutions to help them achieve their goals.

Image credit: Ultrium