Chinese SSD manufacturer Shannon Systems has announced the launch of its open-channel SSDs at Flash Memory Summit. With open-channel SSDs the firmware of the drive only performs some basic tasks, the rest is handled by the NVMe driver of the operating system.
(Specifications of the open-channel SSDs from Shannon Systems)
Open-channel drives are either in the U.2 or PCIe card form-factor and only handle some basic flash operations. Wear leveling, error handling and S.M.A.R.T health management is performed by the controller chip in the drive, the rest of the operations, such as garbage collection and assigning logical addresses to flash cells are handled by the NVMe driver of the OS.
Open-channel SSDs have several benefits. E.g they reduce overhead and allow applications to tell the drive how much performance they need, after which the drive will split up the available resources. Also, storage space and processing resources can be distributed amongst multiple users or applications. It also allows the SSD to utilize both the CPU and RAM memory of the host computer instead of being limited by the processing power of the SSD controller.
Shannon Systems currently lists two open-channels SSDs on its website. One PCIe card and one U.2 SSD that are both available in capacities up to 7.6TB. The PCIe card should be able to achieve sequential reads of up to 1,000,000 IOPS. The U.2 drive should be able to perform random reads at a maximum of 800,000. Random writes are with 180,000 and 140,000 significantly slower.
Open-channel SSDs can be used with Linux through the LightNVM project. Microsoft recently also announced support for open-channel SSDs.
Shannon Systems also announced that its open-channel drives are already in use by Chinese online retail giant Alibaba.
