Tuesday, October 15, 2013

Disk vs. tape from Sentia’s perspective

By: Paul Oh   Categories:Storage and Data Management, Data Protection

Disk vs. tape is a very hot topic these days and is on most people’s radar for their backup solution. It’s also a polarizing topic – different people and vendors have different recommendations and solutions.

So what’s the answer? 

Since one size does not fit all (as is the usual case in IT), you need to do due diligence to come up with the best solution for your environment. 

Consider the following factors:

Cost - What is the dollars per TB to store the backup data? Short-term and long-term costs.

Administration - What is the administration and maintenance overhead?

Security - How secure is the backed-up data?

SLAs – RPO / RTO 

  • Recoverability of data
  • Data Retention
  • Data Archiving
  • Data Copying

Future Proofing 

  • Scalable solution
  • In line with future technology and trends
  • Will data still be readable in the future?

Traditionally tape has been the de-facto storage choice for backups, but lately (the past five years) disk has become a strong viable option.

From JBOD (just a bunch of disks), disk has evolved to become an intelligent media for storage. Disk software has enabled disk capabilities like caching, deduplication, compression, encryption, replication and advanced Raid technology. Also, Flash, SSDs and hybrid disks model are becoming popular and gaining traction.

At the same time, tape has evolved too – those old mainframe 3480 tapes (210MB capacity) can still be seen at some data centres, but now we have LTO6 tapes 2.5TB / 6.25TB (native / compressed) capacity tapes with LTO7 and LTO8 in the future roadmap. 

Disk

Disk has become a popular backup storage media. The biggest benefit of disk being the access speed compared to tape (tape mounts, loads, forward and rewind times are slower than disk). Also with disk, backup administrators don’t have to suffer the traditional tape library /drive hardware head-aches (which seems to be the #1 complaint from backup administrators).

However, disk is more expensive than tape. Some of that cost can be offset by using software enablers like deduplication, compression and disk to disk replication along with high capacity disk drives. On the Security side, hardware and software encryption is available on disks to keep the data secure.

Tape

Cost per TB, tape is still the big winner. Also, tape is a good choice for long-term archiving of backup data. Tape does not have the access speed of disk, but in terms of storage capacity tape still is superior with room to grow. To provide this point IBM / Sony recently demonstrated a working 29TB native capacity tape. 
On the security side, tape can be encrypted at the hardware and software level. So tape is still a consideration in the backup world.

Virtual Tape

Another neat choice is the virtual tape library (VTL) model. VTL uses software to emulate a tape library to the backup software, but the backend is disk or a disk and tape combo. VTL eliminates the tape mount, load and access times. Most manufacturers have a VTL solution available.

Backup Software

Backup software is the glue that holds the disk and or tape solution together. Your choice of disk and tape has to be integrated with the Backup software, as the Backup software will determine how you can use the disk and or tape. The Backup software will typically have limitations that will steer your choice one way or the other, and therefore it is important to know the Backup software limitations.

To find out more about backup solutions, please consult with us at Sentia.

Paul Oh, Vice President of Technical Services
Sentia

Sarah Warsi
Sarah Warsi

Paul Oh

As marketing manager, Sarah plays a key role in managing Sentia's marketing efforts including developing the overall marketing strategy and direction, digital and social media management, to campaign development and execution.

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Full biography

As marketing manager, Sarah plays a key role in managing Sentia's marketing efforts including developing the overall marketing strategy and direction, digital and social media management, to campaign development and execution. She holds a degree in Journalism from Ryerson University.

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