4.091 bytes

Service Hints & Tips

Document ID: MCGN-3QGQU9

This document is provided to IBM and our Business Partners to help sell and/or service IBM products. It is not to be distributed beyond that audience or used for any other purpose.

Servers - Intermittent False DDDs in a 3518 Disk Enclosure

Applicable to: EMEA

Symptom
- Intermittent false DDDs will be reported when "Daisy chaining" backplanes via a ServeRAID Adapter (I & II).
- Problem occurs ONLY when Daisy Chaining.
- This is REGARDLESS of the length of SCSI cable connecting the 3518 to the server.
- Although the SCSI bus length may be within specification for F/W operation, the cable's impedance can cause intermittent problems in this configuration.

Problem Isolation Aids
Only occurs when "Daisy chaining" backplanes via a ServeRAID adapter.

	Option P/N	FRU P/N
ServeRAID	70G8489	06H9334 or 76H6875
ServeRAID II	76H3584	76H3587

Fix
When daisy chaining backplanes in a 3518 External Disk Enclosure, always install a F/W SCSI Repeater card.
F/W SCSI REPEATER

OPTION P/N	FRU P/N
94G7585	93H6409

	Search Keywords	PCSERVER, D/T3518, DDD, SERVERAID, 70G8489, 76H3584
	Hint Category	RAID
	Date Created	06-01-98
	Last Updated	11-02-99
	Revision Date	11-02-2000
	Brand	IBM PC Server
	Product Family	Rack/Storage Enclosures, ServeRAID
	Machine Type	3518, Various
	Model
	TypeModel
	Retain Tip (if applicable)	H057420
	Reverse Doclinks and Admin Purposes	USA=N, EMA=A, AFE=N, Owning B.U.: EMA