How to check if tape drives are detected in the system?

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux (RHEL)
    • tape drives

Issue

  • How to check if tape drives are detected in the system?

Resolution

  • Check to see if the expected tape drives are present in the kernel configuration

    • If the tape drive is detected, you should see something like the following in the /var/log/dmesg file from sosreport or in dmesg command

      st: Version 20070203, fixed bufsize 32768, s/g segs 256
st 3:0:9:0: Attached scsi tape st0
st0: try direct i/o: yes (alignment 512 B)

    • In /proc/scsi/scsi file, you should see similar to 

      Host: scsi3 Channel: 00 Id: 09 Lun: 00
Vendor: HP       Model: C5713A           Rev: H304
Type:   Sequential-Access                ANSI SCSI revision: 03

  • If one or more tape drives are not present as expected, rescan the scsi host bus adpaters:

    • as root: find /sys/class/scsi_host -maxdepth 1 -name "host*" -exec sh -c 'echo "- - -" > {}/scan' \; , or
    • if package sg3_utils is installed use rescan-scsi-bus.sh
    • recheck /proc/scsi/scsi or `lsscsi' output to verify the expected tape drives are now present
    • if after rescan of the scsi bus, the expected tape drives are still not present, raise a Red Hat support case

  • Once the tape drives are detected check the status by running the following command

    #mt -f /dev/st0 status

Note : st module should be present to detect the tape devices.

[root@host1 ~]# modinfo st
filename:       /lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/scsi/st.ko
alias:          scsi:t-0x01*
alias:          char-major-9-*
license:        GPL
description:    SCSI tape (st) driver
author:         Kai Makisara
srcversion:     90119E15C8FC0B44A345478
depends:        
vermagic:       2.6.32-431.el6.x86_64 SMP mod_unload modversions 
parm:           buffer_kbs:Default driver buffer size for fixed block mode (KB; 32) (int)
parm:           max_sg_segs:Maximum number of scatter/gather segments to use (256) (int)
parm:           try_direct_io:Try direct I/O between user buffer and tape drive (1) (int)
parm:           try_rdio:Try direct read i/o when possible (int)
parm:           try_wdio:Try direct write i/o when possible (int)
[root@host1 ~]# lsmod |grep st
xt_state                1492  2 
nf_conntrack           79758  2 nf_conntrack_ipv6,xt_state
[root@host1 ~]# modprobe st
[root@host1 ~]# lsmod |grep st
st                     38398  0 
xt_state                1492  2 
nf_conntrack           79758  2 nf_conntrack_ipv6,xt_state
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