Direct Attached Storage (DAS)
Direct-attached storage (DAS) is computer storage that is directly connected to a computer via PCIe, SATA, SAS, eSATA, NVMe or USB and is not directly accessible from other computers. In professional environments, the individual hard disks in a server are called direct attached storage, which also applies to external mass storage (raid systems, HDD/SSD expansion boxes that are connected directly to the server via NVMe, SCSI, SATA or SAS interfaces. Corresponding storage usually enables higher performance compared to network storage, because data to be read or written is not slowed down by networks. Security problems no longer exist, as failures have become extremely rare due to the use of software and hardware raids, in particular the ZFS file system and redundant power supplies.
Just a Bunch Of Disks
Our HDD/SSD expansion boxes (JBODs) have redundant, highly efficient power supplies and can be equipped with four to ninety 2.5"/3.5" drives. They are usually connected via intelligent SAS backplan. SAS backplans are usually also suitable for connection to several servers, each of which reserves a part of the units for itself and can be taken over automatically or by manually switching external SAS connections from another server in the event of an error. Operation continues virtually without delay or after a short interruption.
Just a Bunch Of Flash
Our JBOFs are designed to provide PCIe gen 3 connection from end to end (CPU to SSD). They have redundant, highly efficient power supplies and can be equipped with four to 32 2.5" M.3 SSD drives.
Additionally, we leveraged the existing Open Vault (Knox) SAS JBOD infrastructure to provide a faster time to market, maintain a common look and feel, enable modularity in PCIe switch solutions, and enable flexibility in SSD form factors. The block diagram below shows the topology that has been implemented.
See JBOF storage extensions