Key Factors that Affect Computer Storage Performance

Here’s a collection of interesting trivia about storage.

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Small files transfer slower than large files, especially on hard drives. Every file has at least two parts: a directory entry and data. When you transfer a file, the HDD heads need to jump first to the directory location, then the data location. The more the heads jump, the slower the overall file transfer speed.

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Just to begin with, the all-digital nature of SSDs makes them very fast. Even better, the lack of moving parts means that delays caused by the HDD drive heads jumping from place to place no longer exist. This is also why SSDs are better for multicam editing – they have no latency caused by jumping drive heads.

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There are two types of SSDs: SATA and NVMe. SATA SSDs generally transfer data around 500 MB/second, depending upon how they are connected. NVMe SSDs can transfer data up to 3,000 MB/second, depending upon how they are manufactured and connected to your computer. SATA SSDs tend to be cheaper. Most SSDs sold for performance are NVMe SSDs.

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Hard disk drives (HDD) spin at three different speeds: 5400 rpm, 7200 rpm, and 10,000 rpm. 5400 rpm drives are best for servers because the slower speed means they last longer and hold up better to the constant access of a server. 7200 rpm drives are best for locally attached storage, both single drives and RAIDs, because they provide faster data transfer speeds. 10,000 rpm drives are generally not worth the cost. Instead, if you need that much speed, switch to SSDs.

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HDDs use two different methods to record data to disk: CMR and SMR. CMR (Conventional Magnetic Recording) drives are faster but don’t hold as much data. SMR (Shingled Magnetic Recording) drives hold more and often cost less, but take longer to record (write) data because of how the data tracks overlap on the platter. If you want better performance, choose CMR drives. However, drive manufacturers don’t always label SMR drives as SMR; hoping you won’t notice. SMR drives tend to be used for very high capacity drives. Be sure to verify whether the drive uses CMR before purchasing it.

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How you connect a drive affects its speed. Thunderbolt 3/4 is faster than USB 4.

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If you have the choice, connecting a Mac to a server via SMB is faster than other options.

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The reason LTO drives are so expensive is the manufacturing cost of the tape heads. These are so hard to manufacture that only 10% pass quality control. This low success rate means a lot of manufacturing costs are spent creating products that don’t work.

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If an LTO tape head fails at one level – say LTO-9 – it is tested at a lower level, which has less stringent specs. Heads that fail at LTO-9 often work perfectly for LTO-8 or LTO-7.

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The same is true for the platters in a spinning hard disk drive. If a platter fails to hold data at the highest density, manufacturers keep testing it until they find a data density that the platter can reliably support.

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RAIDS that use software for control increasingly outperform RAIDs that use hardware control. This is because the computers running the software are faster – and provide more flexible options – than traditional RAIDs.

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If you daisy-chain multiple Thunderbolt devices together, they all share the bandwidth of that one connection to the computer. This means that if one device is using 80% of the bandwidth – say to transfer files – the remaining devices can only access the 20% of bandwidth that’s left.

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SSDs require energy to write or erase data. They require virtually no energy to read it. This means that SSDs used principally for reading data will last longer than those used constantly to write data.

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SSDs can hold data for 15 years or longer, depending upon how they are stored. For best results, store SSDs that are not connected to your computer in a metal box to protect them from EMF radiation.

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