Re:What we learned about SSDs in 2015
by baruch on Friday December 25, 2015 @11:37AM
(#10791585)
Where does one find 10us reads? The NAND is usually with a Tread of 50 to 100 us so just the NAND operation itself is more than 10us.
Tprog is around 1ms and Terase can be upwards of 2ms.
All in all this means a large variability in read performance depending on what other actions are done on the SSD and how well the SSD manages the writes and erase operations in the background.
This doesn't even change with the interface (SAS/SATA/PCIe), those add their own queues, link errors and thus variability.
Then you have the differences in over provisioning that allow high OP drives to mask out better the programming and erase processes.
Tprog is around 1ms and Terase can be upwards of 2ms.
All in all this means a large variability in read performance depending on what other actions are done on the SSD and how well the SSD manages the writes and erase operations in the background.
This doesn't even change with the interface (SAS/SATA/PCIe), those add their own queues, link errors and thus variability.
Then you have the differences in over provisioning that allow high OP drives to mask out better the programming and erase processes.