When adding standalone tape drive to Linux CentOS 7 smart client we see WARNING! No standlone tape drives were found on the selected client (4038945)

Operating system CentOS 7

NetVault version 11.0

Using NetVault add device option and selecting “Single physical tape device”  to a smart client we see “WARNING! No standalone tape drives were found on the selected client”

Logging onto the Linux CentOS 7 smart client we issue the following commands

cat /proc/scsi/scsi  < FIGURED YOU MEAN THIS?
==================

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
 Vendor: QUANTUM  Model: ULTRIUM 5        Rev: 3180
 Type:   Sequential-Access                ANSI  SCSI revision: 06

lsscsi -g
=============

[0:0:0:0]    tape    QUANTUM  ULTRIUM 5        3180  /dev/st0   -

This show that the tape can be seen but there is no SG driver loaded.

We issue the “modprobe sg” command and issue the command below again we see that the SG driver is now loaded.

lsscsi --generic

[0:0:0:0]    tape    QUANTUM  ULTRIUM 5        3180  /dev/st0   /dev/sg3

The tape drive will now add in NetVault but a reboot of the smart client would see the sg driver no longer loading and the tape drive unusable.

SG driver not loaded on boot

This appears to be an issue with CentOS and certain versions of CentOS 7.* not loading the SG driver on startup.  The fix may well be to upload to the latest version of CentOS 7.

If the problem remains there are multiple articles available giving solutions for this.  Below is what seems to be the easiest and quickest resolution to the problem.  Please feel free to use this workaround but if you have any concerns please consult the Linux administrator before using this workaround.

1. Create the file /etc/modprobe.d/sg.conf

2. The file should contain one line only with the word "sg". Like this:

sg

3. Reboot

4. Check that it works using the “lsscsi --generic”  command as seen below.

[root@analyze1 ~]# lsscsi --generic
[0:0:0:0]    tape    QUANTUM  ULTRIUM 5        3180  /dev/st0   /dev/sg3