HP Disk System 2300 HP StorageWorks Disk System 2300 User's Guide(This manual - Page 87

Rationale Sites choose DIP switch options according to their priorities and preferences. High availability sites, for example, may want automatic bus reset on whereas high performance sites may choose to turn it off. The following table gives some of the typical reasons for choosing specific DIP switch settings. Table 9. DIP Switch Usage Switch 1 Reasons to Set OFF (|) Reasons to Set ON (0) 1. Full Bus 2. SES/ SAF-TE a. Full-bus mode is the only way to access all 14 disks with one BCC. b. With two BCCs, full-bus mode allows two external connections to the bus. c. Full-bus mode with two BCCs gives redundant environmental services. SAF-TE is required for NT. a. Split buses allow you to mirror disks within the disk system. b. Split-bus mode uses fewer IDs on the bus, improving bus performance. SES is required for HP-UX . Switch 2 Reasons to Set OFF (|) Reasons to Set ON (0) 1. Bus ResetHot Swap Disk 2. Bus ResetPwr Fail 3. Bus ResetHot Swap BCC Automatic bus reset reduces the chances of data corruption and saves the 30 to 60 seconds that the host would spend determining that a disk is unavailable. Bus reset signals the host to resend outstanding I/O requests. a. No bus reset reserves bus control to the host. b. No bus reset avoids resetting the entire bus for one disk. SCSI bus is held in reset Bus control is restricted as power goes down, thus to the host. avoiding data corruption Automatic SCSI bus reset reduces the chance of data corruption when a BCC is inserted or removed from the disk system. a. No bus reset reserves bus control to the host. b. No bus reset avoids resetting the entire bus for one disk. Configuration 87 Configuration