Storing Deduplicated Virtual Machine Images on Tape Cartridges

For at least the last 20 years we have heard that “tape is dead”. But in fact, storage managers in most of the world’s enterprise IT organizations use a combination of disk and tape as part of a tiered data protection storage strategy.

Tape isn’t going away anytime soon. According to a December 2010 ESG brief titled: “NERSC – Success with Primary Data on Tape”, nearly half of the world’s data is stored on magnetic tape. Indeed, all 10 of the world’s 10 largest banks rely on tape storage for backup and archive data retention. The same can be said for each of the 10 largest telcos in the world; and eight of the 10 largest pharmaceutical firms.

So tape is still here, featuring higher speeds and higher capacities. To keep a copy of your virtual machine images offsite, simply copy your images to tape and send them offsite to Iron Mountain or some other 3rd party storage facility. Problem solved.

Well, not exactly. Tape drives compress, however they do not deduplicate. So that 50TB of storage holding 1,000 virtual machine images translates into roughly 25TB of tape storage (at 2:1 compression).

And Iron Mountain charges by the cartridge, to say nothing of your own management time. Offsite storage expenses for data stored on tape is tied to the number of physical tape cartridges stored, so reducing the cartridge count through deduplication makes perfect sense.

CRUNCH Your Iron Mountain® Bills

CRUNCH is delivered as a Virtual Deduplication Appliance in Microsoft VHD format, allowing CRUNCH to run on most existing backup servers or wherever your virtual machine images are stored. Note that delivering CRUNCH as a Windows VHD does not restrict its use to Hyper-V virtual machines. CRUNCH deduplicates all virtual machine image types.

CRUNCH is delivered as a Virtual Deduplication Appliance, supplied in Microsoft VHD format, allowing CRUNCH to run on most existing backup servers or wherever your virtual machine images are stored. Note that delivering CRUNCH as a Windows VHD does not restrict its use to Hyper-V virtual machine images. CRUNCH deduplicates all virtual machine image types (VHD, VMDK, VDI, etc.).

Following is an example of the VM image data reduction capability of CRUNCH:

We created 24 Windows Hyper-V virtual machines in the BridgeSTOR lab. Those 24 images required 330GB of storage capacity. When we performed a compression-only test to tape (using LTO tape drive compression alone – without CRUNCH), the original 330GB of data was reduced to 123GB (a 2.7:1 data reduction ratio resulting from compression). However, following CRUNCH processing and tape drive compression, the original 330GB of data was reduced to just 16GB (20.6:1 data reduction – or a roughly 8X improvement in data reduction over compression alone).

We are not suggesting that your results will be the same. We only offer a data point as a place from which to start.

Determining How CRUNCH Can Work for You

The CRUNCH Virtual Deduplication Appliance is available for download and evaluation from the BridgeSTOR website. Please register to download the software, the user guide and the applicable release notes.

You can easily translate the benefits of storing deduplicated data on tape cartridges into substantial cost savings by reducing the time you spend managing tapes, reducing tape acquisitions, tape library slot charges, transportation and monthly Iron Mountain charges. In the virtual machine image disaster recovery and archive applications, the benefits of BridgeSTOR’s CRUNCH are compelling.

When sending data to tape, BridgeSTOR recommends that the tape drive compression and encryption (as deployed on LTO tape drives, for instance) be employed. Using CRUNCH with outboard compression and encryption enables you to keep a copy of your data protected offsite. With data dramatically reduced by CRUNCH deduplication and tape drive compression, you can CRUNCH your monthly Iron Mountain bill.

The following illustration should clarify the process:

Five (5) Key Business Benefits

Space and cost reduces Virtual Machine images (VHD, VMDK and other formats) stored on tape through CRUNCH deduplication coupled with tape drive compression
Reduces the number of tape cartridges required to store DR and archive copies of VM images, reducing Iron Mountain (or other) off-site space requirements and costs
Reduces tape cartridge acquisitions
Reduces tape transportation expenses
Reduces the number of off-site tape cartridges you need to keep track of