iSCSI uses Ethernet to carry block storage, which has low cost and flexible networking. However, link sharing and long optical paths are two major hidden dangers. When building an iSCSI storage network, it is recommended to do three things first: calculation, isolation, and budget, and then talk about card and module selection.

Step 1: Infer bandwidth based on business load

First convert: the sustained throughput of a gigabit link is about 100MB/s, and the sustained throughput of a 10G link is about 1GB/s. There is a write penalty for writing small blocks in RAID 5 arrays, which needs to be multiplied by a coefficient. In engineering, it is usually recommended that the link utilization rate does not exceed 60%. If the service peak requires 600MB/s and 10G is barely enough, it is recommended to directly plan a 25G link or dual-port aggregation. For example, usePCI-EX16 25G four-port optical fiber network card (Intel E810 chip)Take two independent paths to share traffic.

Step 2: The storage network must be isolated

• Storage traffic uses an independent VLAN and an independent switch, and does not share the uplink with business Internet access.
• Change the MTU of the initiator and destination to 9000 to enable jumbo frames. The entire path must be consistent, otherwise packets will be lost.
• The network card is dual uplinked to two storage switches, and cooperates with the system multi-pathing software to avoid the failure of a single switch causing the entire cluster to be disconnected.
• Reserve an independent management channel and do not let the storage network become the only outlet for the host.

Step 3: Leave a 3dB margin in the optical path budget

Interconnection with the same computer room is availableSFP+ 10G single-mode dual-fiber 10km optical module paired with LC-LC single mode dual core jumper, after accumulating the losses of jumpers and adapters step by step, compare them with the loss budget of the module. It is generally recommended to retain a 3dB margin. Dust is the primary cause of low power. During acceptance, the luminous power is measured link by link and kept as a file, so that there is evidence for subsequent troubleshooting of slowdowns.

The number of selected cards and optical path calculation details vary greatly depending on the project. You can call EB-LINK at 0755-83179002 to obtain a configuration list. The modules and jumpers are tested one by one before leaving the factory and then shipped.