Testing Multiple Drives for Consistency for a RAID or Similar

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Among its many features, diglloydTools DiskTester offers a run-area-test command that can be used for relatively fast characterization of drive performance across its capacity. The results can be graphed to get a good idea of the drive performance.

For example, suppose a high performance RAID is envisioned: one laggard can cut the performance, since the slowest drive determines the peak speed.

As shown below, 8 samples were tested, and one of those eight is a significant laggard; this slower drive is best set aside as a cold spare or backup drive.

While DiskTester can test any number of drives simultaneously (via command line), testing should take care not to saturate the bandwidth; for example four fast hard drives can demand almost all of the Thunderbolt v1 bandwidth, and other devices on the bus could suck up bandwidth, disturbing the results.

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diglloydTools DiskTester: performance across volume capacity for eight drives
disktester run-area-test --iterations 5 --test-size 4G --delta-percent 5

Some of the capabilities in diglloydTools

Aside from testing hard drive or SSD or RAID performance and reliability with DiskTester, data integrity with IntegrityChecker is a must-have workflow tool for anyone with important data:

• Detecting Corruption / Validating Data Integrity Over Time and Across Drives and Backup/Restore
• What an Impaired SSD Looks Like
• How to Safely Transfer Data or Verify Backups
• Example of Verifying Data Integrity.
• Are Your Backup Drives Still Functional? Are Your Files Subtly Damaged?
• How to Automate DiskUtility Verification of Mounted Volumes.
• Selling that Computer? Wipe Out Personal Files First
• Search for diglloydTools articles.