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Title
The following error appears on our main system console: NOTICE: cha: SCSI data underrun ha=1 id=2 lun=0 cmd=05 blk=0 len=8185 Data arriving from a SCSI peripheral under-filled storage (chaN07)
Keywords
CHA Compaq BackupEDGE underrun edge console SCSI host adapter
Product Release(s)
03.00.0x 02.02.0x 02.01.0x 02.00.0x 01.02.0x, 01.01.08
Operating System(s)
SCO Openserver 5.0x
Problem Description
The following error appears on our main system console: NOTICE: cha: SCSI data underrun ha=1 id=2 lun=0 cmd=05 blk=0 len=8185 Data arriving from a SCSI peripheral under-filled storage (chaN07)

Cause
The COMPAQ host adapter reports this error when BackupEDGE communicates directly to the tape drive. This message is generated when the BackupEDGE software is making an inquiry on the drive or setting hardware block, compression or partition on the tape.

From an software perspective, this error cannot be suppressed through BackupEDGE. For the most part, this error is harmless, however it is a nuisance.

Solution
There are two options to removing this message.

The first is to read Technical Article 105353 from SCO's technical support page, which describes turning off the messages in the cha kernel driver.

Alternatively, you can eliminate this message by configuring BackupEDGE to perform only simple read/write operations with the tape drive.

To do this in 01.01.08 build 5 and earlier, run /usr/lib/edge/bin/edge.resmgr. Select Add new Resource, give it a symbolic name such as tape0, rather than define it as a tape drive, use the left/right arrow keys until the field says "Other Device". Then continue, fill in a description, control node (/dev/xStp0), data node (/dev/rStp0), Seek = "N". Save the device, then exit edge.resmgr. Then run edge.config, type A tape0, then do the same for option E. Save the device and run edgemenu.

For BackupEDGE 01.01.08 build 6 or later, invoke the resource manager (/usr/lib/edge/bin/edge.resmgr), highlight the resource for your tape drive, and edit it. Then advance the cursor to the Interface field, change the type from SCSI to Other. Save the change and exit the resource manager. This will eliminate the cha error, however, you will lose some functionality with edge's ability to control the tape drive as described above. You will not be able to perform any Fast File Restores or indexing using this type of device. However basic backup/verify/restore operations will be unaffected.

Notes
There is also a technical article on SCO's web site http://www.sco.com/ta Article reference id is 105353
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Last Updated - 2018/05/16

 

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