Selecting a hard drive: SSD vs HDD

At one stage, not so many years ago, for most people it was easy to decide what drive to select when buying a computer: a spinning drive (HDD).

A solid state drive (SSD) option was simply too expensive and could not offer the capacity.

So buying a hard drive was simple. You’d find the three or four highest capacity drives you could afford, pick the fastest, and, well, that was it!

These days it is a little more difficult as SSD technology has come of age and is now fast overtaking the older HDD technology.

Standard HDD drives contain multiple disks called platters, which are covered in a magnetic coating and then rotated at high speed.

Drive heads then move across the platters, changing the magnetisation of the material beneath to record data, or reading its state to return the stored information.

Both reading and writing data requires a lot of work. Heads must move around, and the platter must spin to exactly the right point before the drive can do anything.

This all takes time, and is the reason why hard drives are one of the major performance bottlenecks in PCs.

Having to move all these components around also means there’s a constant power drain, which is an issue with laptops.

The drive head gets incredibly close to the platter – a tiny fraction of the thickness of a human hair – so if there’s a shock at the wrong time the two may collide, damaging the drive and losing data.

Drive manufacturers employ a range of technologies to prevent this from happening, and as a result these head crashes are rare.

The SSD has recently come into its own. Jarrett Potts, VP marketing and sales, Huawei, put forward the suggestion that solid state drives are more affordable because of their longer life expectancy.

The debate is on: has SSD advanced to the point where it can compete with HHD in terms of capacity and price?

According to Potts, Huawei is already providing some models of its SSD for the same price as HDD at the same capacity, and the company is planning to extend this to all sizes of HDD in the near future.

He said that capacity and price are now flat for tier one storage which is currently dominated by 15 000 rpm disks, and that Huawei now provides the SSD drives at the same price point per TB.

Initially mean time to failure of drives used to be a major issue but within the last 18 to 24 months SSDs have been now providinglonger life stats.

Comparing SSD with HDD reliability, the speed of SSD is usually about 900% faster than 15 k HHD drives and the reliability is now almost twice that of the HDD drives.

Potts said that the return on investment on SSD is superb, as the same price is paid for the same capacity as 15 000 rpm disks, but with a 900% speed boost and the extra benefit of a much lower operating cost.

Heating and cooling is 20 to 30% less, while power usage is up to 70% less. Couple that with a seven- to nine-year drive life and this gives the SSD drives a huge advantage over HDD, according to Potts.

There is a great usage case for hybrid systems (HDD and SDD) when the HDDs are 10 000 rpm and lower.

The size and cost of those drives will make it difficult for SSD to match the return on investment within the next 12 to 18 months but with the rapid decline in cost, it is a possibility.

10 k and 7,5 k drives are great for non-production and long term storage.

Potts concluded by saying that spinning drives (HDD) have not lagged in development.

HDD has many years left in it but the high-end production systems should be equipped with at least 40% SSD now that cost is not an issue.

SSD is the technology for the next three to five years and is the foundation for the next generation of tier one storage.

Source: EE Publishers

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