Solid State Drives and how they work?
Solid State Drives provide rapid access to information, they achieve this by having no moving parts. The data in a solid state drive is always available and it takes micro seconds to retrieve compared to a disk drive taking milliseconds so accessing the data is 1,000 times faster than disk drives. The physical location of data doesn’t matter on a solid state drive, read speeds are consistent and disk fragmentation isn’t a problem. SSD use less power compared to hard drives and make them suitable for use in notebooks and generate less heat.
What is a Solid State Drive made of?
A solid state drive typically contains lots of NAND flash memory cells, these cells are different to normal memory as they retain the information once written or when the power is turned off. You can read/write an SSD 10,000 times using MLC or 100,000 times using SLC memory although the cost is considerably more for the SLC option. All SSD have a wear controller and this checks each cell to see if it is degrading, if it is then that block is written to another cell and the degraded cell is marked as bad. They are lighter than normal hard disk drives and are smaller in height. A solid state drive also has a much higher shock rating against being dropped and run silently. They also do not suffer from magnetic interference.
How fast are Solid State Drives?
These are typically 2-4x faster than hard disk drives and the disk transfers rate is up to 5x faster. It is IOPS that a Solid State Drive will perform much faster so if our single hard drive has an IOP speed of 200 a solid state drive would typically have an IOP speed of 50,000+!
What capacity Solid State Drives are available?
At present SSD capacities start at 32GB rising to 1024GB and typically rise in increments as shown below.
As prices come down the capacity will increase.
There are two types of SSD drives
If you need SSD for home use then you can use consumer grade drives, these do not provide the extended warranty, perform as fast and do not have advanced error correction algorithms. The professional grade solid state drives typically have a 5 year warranty are faster and have advanced wear controllers ensuring that the SSD does not suffer from data loss. The downside is that SSD consumer grade are much cheaper than professional.
Would you use SSD in a RAID?
This question arises many times and the answer is not straight forward. It depends on the application and whether you are going to be doing lots of writes or reads. We have mentioned earlier that SSD suffer from wear but the built in wear controller of SSD overcomes this to a certain extent. If you want to build a RAID system with 2 or 4 drives you could use consumer grade SSD, if you need to fit more than 5 drives then I would recommend professional grade SSD.
If you fit 16x SSD in a RAID chassis then the performance these drives would generate would overload the RAID controller and system causing a hung state. When using solid state drives in a RAID you must ensure that the RAID controller can handle the performance otherwise you would have spent a lot of money of high performing SSD that you can’t use.
Ideally, it would be more beneficial to create a RAID 1 or 10 array and run your application on these and the rest of the drives can be normal SAS or SATA.
Below is a list of SSD manufacturers products we can supply if you are looking for a vendor that isn’t listed please call us.
A solid state system will perform significantly faster than a similar equipped hard drive system. SSD is limited by capacity and price compared to spinning disk drives and you need to be aware of where and when you can use them. For more advice when looking for a solid state disk solution please call us.
If you want to know more about Solid State Drives please visit this link as it explains how an SSD works.