Disks can be connected to x86 servers in different ways:
local SAS connections: connection of the internal system disks (not released for use under BS2000) and (only for SU300, SU300B) of the rack-internal ETERNUS JX storage system
Fibre Channel (FC peripherals, e.g. ETERNUS DX/AF)
Ethernet (Net-Storage)
All input/output operations to the peripherals are directed via the I/O processors (X2000). The performance of the I/O processors is very good, and also more than sufficient for all x86 servers in the event of very heavy loads.
The corresponding interfaces are operated in X2000; the local peripherals are connected via corresponding PCIe controllers.
SAS connection
As Direct Attached Storage (DAS) the storage systems of the ETERNUS JX series enhance the storage capacity of the x86 servers via a high-speed SAS connection.
When an optional ETERNUS JX system is used which incorporates a backup battery unit (BBU) for the write cache and is connected via SAS RAID, a BBU Relearn Cycle is performed every 30 days. The BBU Relearn Cycle takes up to 15 hours. It discharges and charges the BBU fully several times. During this time the write cache is disabled; the additional acceleration which it provides is then not available. In certain applications this can result in longer runtimes or response times. The BBU Relearn Cycle can be configured on a customer-specific basis by customer support so that, for example, the BBU Relearn Cycle is only executed at the weekend.
FC connection
On x86 servers, PCIe controllers with a capacity of up to 32 Gbit/s (SU310) can be used.