IBM tape systems are designed for high-speed data transfer, capable of achieving a maximum performance of 750 MB/s with 2.5:1 compression. Natively, without compression, the speed is 300 MB/s.
Understanding IBM Tape Performance
IBM tape drives, particularly the latest generations, offer impressive data transfer rates crucial for efficient backup, archive, and disaster recovery operations. The speed of tape is typically measured in megabytes per second (MB/s) and can vary significantly based on whether data compression is utilized.
Native vs. Compressed Throughput
The speed of an IBM tape drive is often quoted in two ways: native throughput and compressed throughput.
- Native Throughput: This is the raw speed at which the tape drive can write or read uncompressed data. For IBM tape, the native speed is 300 MB/s. This is the baseline performance without any data reduction techniques applied by the drive.
- Compressed Throughput: Modern tape drives employ hardware compression, which can significantly boost the effective data transfer rate. With a typical 2.5:1 compression ratio, IBM tape systems can achieve speeds up to 750 MB/s. This means that 2.5 times more data can be written to the tape in the same amount of time, assuming the data is highly compressible.
Here's a quick summary:
| Performance Metric | Speed (MB/s) | Notes |
|---|---|---|
| Native Speed | 300 | Without data compression |
| Compressed Speed | 750 | With 2.5:1 hardware compression ratio |
Factors Influencing Tape Speed
While the maximum speeds are impressive, the actual throughput experienced in a real-world environment can be influenced by several factors:
- Data Compressibility: The effectiveness of compressed throughput heavily depends on how well the data can be compressed. Highly compressible data (e.g., text files, databases) will achieve closer to the maximum compressed speed, while already compressed data (e.g., JPEG images, MP3s, encrypted files) will see little to no benefit from tape compression, effectively running at native speeds.
- Host System Performance: The server or workstation sending data to the tape drive must be able to keep up with the drive's speed. Factors like CPU utilization, I/O subsystem performance, and network bandwidth (if data is coming from a network share) can create bottlenecks.
- Data Stream Consistency: For optimal tape performance, a continuous stream of data is essential. If the data flow is intermittent, the tape drive may have to stop and reposition, significantly reducing the effective throughput. This is known as "shoe-shining."
- Interface Type: The interface connecting the tape drive to the server (e.g., Fibre Channel, SAS) and its generation can also impact the maximum achievable speed.
- Software Overhead: Backup software, encryption, and deduplication processes running on the host server can add overhead, potentially limiting the data transfer rate to the tape drive.
For further technical specifications, you can consult various industry resources and documentation.
