Spectra T50e - Page 351

Chapter 12—Library Troubleshooting Troubleshooting Library Hardware Issues
August 2017 User Guide—Spectra T50e Library
348
SCSI Connectivity KeeptheseguidelinesinmindasyouplanyourSCSIconnections:
 DonotexceedSCSIbuslengthrestrictions.Themaximumallowablelength
ofanLVDSCSIbusis39feet(12meters).
LTO‐3:
 AmaximumoftwoLTO‐3SCSItapedrivescanbedaisy‐chainedona
singleSCSIbus.
 Whendaisy‐chainingLTO‐3tapedrives,useacablelengthofatleast12
inchesandthatdoesnotrequiremakingtightbendsinthecable.
LTO‐4:SpectraLogicdoesnotsupportdaisy‐chainingLTO‐4drives.
 General:
 Keepinmindthateachdaisy‐chainedLTO‐3driveincreasesthetotal
lengthoftheSCSIbus.
 ConnectingmultipledevicesonasingleSCSIbuscanimpactthe
performanceofalldevicesonthebus.Thedatatransmissionratetoany
driveonthebusislimitedtothemaximumtransferrateoftheSCSIbus.
 SpectraLogicdoesnotrecommend,anddoesnotsupport,daisy‐chaining
otherSCSIdevicesonthesameSCSIbusasthedrivesinthelibrary.
Note: Althoughamaximumof15devicescanbeconnectedtoasinglewide
LVDSCSIbus,attachingmorethantwodevicestoasingleSCSIbuscan
potentiallyhav eanegativeimpactontheperformanceofalldevicesonthebus.
SCSI Bus
Termination
IftheSCSIbusisnotproperlyterminatedyoumayexperienceoneormoreof
thefollowingfailuresymptoms:
 Read/Writefailures
 Bushangs
 Connectivityissues—tapedriveisnotseenonbusordropsoffbus
 Commandfailures—commandstoatapedrivemayfailwhilecommandsto
otherdevicesonthebusmayworkproperly
IfyouexperiencesporadicerrorsandareusingSCSIdrivesinthelibrary,make
surethattheSCSIbusconnectedtoeachtapedriveisproperlyterminatedat
bothends.
 LTO‐3:IfaLTO‐3tapedriveinthelibraryterminatestheSCSIbus,eitheras
thelastdriveinadaisychainorastheonlydriveconnectedtothebus,install
awideUltra3ActiveSCSIterminatoronthetapedrive’ssecondSCSI
connector.
 LTO‐4:InstallawideUltra3ActiveSCSIterminatoronthetapedrive’s
secondSCSIconnector(donotdaisy‐chainLTO‐4SCSItapedrives).
Issue Resolution