A SSD (Solid State Drive) is a new generation of flash based storage device, which is an equivalent of traditional HDD (Hard Disk Drive). From physical specifications, SSD and HDD are similar to each other, but they store data very differently. Hard disk drive contains spinning platters with the magnetic coating that stores the data information, and the read/write head on the “actuator arm” accesses the data while the platters are spining.
While SSD employed no-moving parts named NAND Flash for data storage instead of magnetic heads inside HDD. Wihtout moving parts, SSD is more durable, run cooler and less power consumption.
Speed: SSD is much faster than HDD on Read/Write Operation, Response time
Durability: Without moving parts, SSD is more robust for harsh environment like shock, vibration, humidity, extend temperature, etc.
Capacity: Combined current NAND Flash development technology, the capacity of SSD supports will become larger and larger
Form Factor: SSD deliveres various form factors besides 2.5-inch and 1.8-inch
Noise: No mechanical structure as HDD has, SSD works more quietly, makes no noise at all
Power Consumption: No power needed to drive the magnetic platter and actuator arm spining, SSD lead to much lower power consumption during opeartion.
Due to the nature of NAND Flash chips, a SSD has a limited number of write cycles before it fails.
SLC: Single-level cell NAND Flash, the current chips processing support 60,000 write cycles
pSLC: New technology to achieve SLC reliability but more effective-cost, normally can support 30,000 to 100,000 times write cycles
MLC: Multi-level cell NAND (2-bits), generally delivers up to 3,000 times write cycles
TLC: Triple-level cells (3-bits) NAND Flash, the latest main stream flash chips, deliver 300~1,000 write cycles, fewer 3D NAND can achieve 3,000 write cycles
In generally, the lifespan of a SSD is related to three key parameters: the NAND Flash deployed, available capacity of the disk and real application mode.
Life (years)=(Drive Capacity x OP x P/E) / WAF/ Workload / 365
|Reliability & Endurance||Higher||High||Low+||Low|
|P/E Cycle||>60,000||30,000~100,000||3,000||300~1,000, 3D-TLC: 3,000|
|Data Retention||10 years||10 years||10 years||5 years|
|Cost per bit||$$$$+||$$$||$$+||$$-|
ECC named Error Checking and Correction or Error Correction Coding, which is a technique used to correct errors in NAND Flash chips. It is normally works with Bad Block Management to help the disk remain stable and reliability during usage.
It is genearlly reports ECC fail if errors are unable to be corrected, and the user will find a “Read Fail” from the device.
The lower reliability of the NAND Flash chips normally demands higher ECC capability.
S.M.A.R.T (Self-Monitoring, Analysis, and Reporting Technology) attribute parameters normally be used as a reference value for SSD health monitoring. But as we know, there isn’t a SSD standard for S.M.A.R.T attributes so far. Secondly, some of the ID’s attributes display blank and others may still use HDD’s ID attributes which is not suitable for SSD (like spin up time). So if the S.M.A.R.T tool is not provided by SSD manufacturer but a third party tools, it’s better to check the meaning of attribute parameters with SSD provider.
Following S.M.A.R.T tools for your reference:
Crystal Disk Info
HD Tune Pro
Crystal Disk Mark