Virtualization is becoming more and more topical in the computer trade magazines. In some articles, virtualization has been hailed as the next frontier of computing. What is computer virtualization and how can you or your clients benefit from it?
What is virtualization?
Virtualization is a method of running other software or hardware applications under a host system. The virtual system and the host system would share the same hardware. Virtualization can allow multiple systems to share one physical computer. For example, an enterprise could invest into a computer system with high processing power and maximum memory, then by using virtualization, an administrator could have three or four operating systems running on that equipment (depending on the processing power of the equipment and the operating system requirements). The benefits of hardware cost savings alone justify you or your client’s attention to this exciting technology.
Recently, Microsoft and VMware (companies specializing in software virtualization) announced that consumers could download their virtualization software at no charge. The results of Microsoft and VMware publicly releasing their virtual host server software to users free of charge encourages more individuals to become familiar with virtualized operating systems. This familiarity, combined with cheap access to massive amounts of storage (with individual disk drives at 700GB and single 1TB drives just around the corner, multi-terabyte arrays are commonplace) and RAID technology becoming more widespread and thereby more accessible, is anticipated to produce a proliferation of virtualization across business types and sizes.
Virtualization doesn’t stop with operating systems; you can also have virtualized applications and SAN storage pools. In line with these resource virtualization concepts, presenting storage components like hard disk drives as tape hardware is known as a virtual tape library, or VTL. The topic of this month’s technical article, VTL technology boasts a high percentage of return on investment, offers ease of installation within an existing archival environment, and affords faster data restores. Additionally, VTL doesn’t mean the end of the investment that has been made into physical tape machines or libraries. The architecture of the backup system can still stream data to a physical tape for offsite storage.
In a nutshell, VTL utilizes hardware and software solutions for redirecting the backup data that would have been sent to the tape library to a large RAID array. The backup software is able to do this (by means of hardware and software) by recognizing the RAID array as a tape drive. Traditional backup options, such as Full, Differential, Incremental, and Snapshot schemas still function in the same way in a VTL. Essentially, the backup schema in place pre-VTL implementation will still be available after migrating to a VTL setup.
Storage Concepts of a Virtual Tape Library
The storage concepts of VTL revolve around streaming backup data to a RAID 0, or RAID 5 configuration. There are several advantages to streaming the data to a disk array first; the principal among them being speed. Benchmark tests have shown that the transfer throughput (from server to backup disk array) is noticeably increased. This is because the data transfer to magnetic tape media is eliminated. Additionally, retrieval of archived data is also much faster because there is no bottleneck due to rewind and fast-forward operations, or of cataloging tape archives and sessions.
Storage for a VTL system can start at the half terabyte range and go into the hundreds of terabytes depending on your needs. Storage can be high-performance Fibre Channel or iSCSI systems. Alternatively, SATA (Serial ATA) and PATA (Parallel ATA) systems are available and are usually lower in cost. All of these storage systems are a good choice for VTL implementations.
VTL software and hardware also support multiple virtual tape libraries. Historically, in environments using a traditional physical tape machine schema employing a one physical tape machine setup it was noticed there was a lot data moving to that one device. To address this data movement issue, IT administrators added multiple tape machines, large tape libraries that employ many tape machines, to spread the workload out and to keep the data transfer balanced. VTL setups offer the same multiplicity of backups running at once, which means you can distribute the archiving process over a greater number of data areas. Despite the virtualization however, the data will still be physically stored on the RAID storage array.
For IT environments that have specific policies regarding offsite storage of data, nearly all VTL systems now support a physical tape library that is connected to the VTL, allowing a consistent flow of archived data to be “re-archived” onto a physical tape—a backup of a backup. This helps to doubly ensure that user files are being protected. The secondary archive is set to a schedule where tapes can be stored or recycled.
Some organizations have produced a VTL setup on a WAN scale. In theory, this enables organizations to host a remote Disaster Recovery site as little as 50 miles away. By utilizing point in time snapshots in conjunction with such a VTL setup, the data restoration during an outage is reduced considerably.
A large number of tape backup applications already employ some sort of tape virtualization. If you have specific requirements in this regard, you should contact your software vendor. So how does the entire system work?
Operation Flow
Operationally, the environment does not change and the scheduled backups still happen as they have already been setup. The hardware and software setup may require some installation depending on the equipment installed, with connectivity details, (IP, SCSI, iSCSI, Fibre Channel) dependent on the topography of the network.
With more setup and configuration a more dynamic, fault-tolerant solution can be installed—all without the overhead, media cost, and tape recycling schedules.
What exactly does virtualization bring to this configuration? Virtualization has the potential to remove tape media from the topography completely. As mentioned previously, products are available that can create multiple virtual libraries or tape machines. The advantage is that multiple backups can be running from different servers all into a storage pool. This storage can perform a less rigorous backup to tape, or another VTL. This second level VTL can be slower disk storage and function as an ongoing backup of the first level backup. Easy availability of products to facilitate creation of VTL environments along with affordable technology has made the dual backup process with different schedules possible.
Data Recovery of VTL storage
Today’s compliance and regulatory laws are requiring organizations to ensure ‘data availability.’ You won’t get an understanding nod from an auditor by saying, “The server you wanted to look at has just failed.” What happens when there is a failure on the storage array that is hosting your first level or second level backup data?
All is not lost! A professional data recovery firm can rebuild and extract the data from storage arrays that are used in VTL systems, focusing on the data contained within the tape archive files post-extraction. Today’s complex archiving software will store the target files with a high compression ratio and internal cataloging method. Only a competent and experienced data recovery firm like Ontrack Data Recovery will be able to deliver the archived data in a timely fashion.
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