| Tape drives remain the leading technology used by | | | | sizes and locations of the files on disk and is generally |
| organizations for backup and archiving. However, the | | | | unpredictable, but can be determined by the use of |
| plethora of tape drives on the market can make | | | | specialised software.Secondly, if data is being |
| choosing the appropriate tape drive a confusing task. | | | | transferred over a network of computers to a |
| How do you select a tape drive that satisfies your | | | | backup server, the network may be incapable of |
| needs without blowing the budget? The following are | | | | supplying data at a sufficient rate. The maximum |
| just some of the main factors to consider.1. | | | | throughput |
| CapacitySelect a tape drive that has sufficient | | | | of a network is predictable and easy to measure, |
| capacity to store your backups. Tape drives are able | | | | based on previous network performance.Consider a |
| to compress data so that more data may fit on the | | | | network using 10BaseT Ethernet. This transfer rate |
| tape, which is why manufacturers specify both a | | | | through this type of network cannot exceed 10MB/s, |
| native capacity and a compressed capacity, usually | | | | so it is immediately apparent that a tape drive |
| with a compression ratio at 2:1. However, | | | | requiring 20MB/s is |
| highly-compressed files such as those in video and | | | | inappropriate.3. Reliability and duty cycleA simple way |
| sound formats are hardly compressible at all. For this | | | | to gauge the reliability of a tape drive is to find out |
| reason, do not heed the specified compressed | | | | the Mean Time Between Failure (MTBF) as specified |
| capacity when choosing a tape drive.A good way to | | | | by the manufacturer. You should note, however, that |
| determine the size of the backup job after | | | | the MTBF is |
| compression is to study logs of past backups. If | | | | usually specified at a certain duty cycle. For example, |
| these are unavailable, it is safe to assume that the | | | | consider a Travan tape drive with a MTBF of |
| data can be compressed at a ratio of 1.4:1, unless the | | | | 370,000 hours at 20% duty cycle. The drive will only |
| hard drive contains an usually large number of | | | | have an average of 370,000 hours between failures |
| highly-compressed files.2. Transfer rateThe transfer | | | | if it is run less than 20% of the time (about 4.8 hours |
| rate of the tape drive is becomes important when | | | | per day), and running the tape drive for any longer |
| there is limited "window of opportunity" in which | | | | will significantly reduce the reliability of the drive.4. |
| backup jobs may run. It is often desirable for | | | | PriceThere is no point purchasing the highest-range |
| backups to take place during the night when network | | | | tape drive if it's simply too expensive. Consider how |
| use is at its lowest.Select a tape drive that is capable | | | | much value-for-money the tape drive will give you. |
| of completing a backup job within your window of | | | | Are you willing to pay more |
| opportunity. For instance, to back up 400GB per | | | | for extra performance? Or do you need to sacrifice |
| night, you will require a transfer rate of about 30GB | | | | some performance to save on costs?If you choose |
| hour.A little known fact about tape drives is that data | | | | wisely, you should end up with a tape drive that |
| must be supplied to them at a sufficient rate in order | | | | fulfils your organization's tape backup and archiving |
| to keep them streaming, or else the tape suffers | | | | needs, without blowing the budget.Linus Chang is a |
| from start-stop motion. | | | | backup expert and the lead developer of |
| This motion severely degrades the life of the drive | | | | BackupAssist -- tape backup software that is simple |
| and tapes and the reliability of backups.There are | | | | and affordable, and perfect for small and medium |
| two usual reasons why tape drive are not be | | | | businesses. Protect your Windows servers, including |
| supplied with data at a sufficient rate. Firstly, the rate | | | | SQL Server and Exchange Server, to tape, REV |
| at which data is read from the hard disk of the | | | | drive, hard drive, NAS and more, at a fraction of the |
| server is insufficient. This rate is dependent on the | | | | cost of other backup software. |