Tape Servers¶
A Tape Server is a computer connected to at least one tape drive and running the cta-taped daemon.
It acts as a tape drive's connection to the outside world, picking up archive/retrieve jobs for the drive to act upon, and buffering data in transit to/from tape on its local disk(s).
On a tape server the SCSI-connected tape drives are exposed in the file system as devices in /dev.
A device is either automatically rewinding, such that the tape is rewound back to its beginning after each read/write operation, or non-rewinding.
/dev/st<X>- Automatically rewinds/dev/nst0- Does not automatically rewind.
Configuring a tape server¶
Configuting correct fibre channel topology of the Emulex HBA¶
Some tape servers are equipped with Emulex HBA:
[root@tpsrv600 ~]# lspci -v | grep -i fibre
81:00.0 Fibre Channel: Emulex Corporation LPe31000/LPe32000 Series 16Gb/32Gb Fibre Channel Adapter (rev 01)
Subsystem: Emulex Corporation LPe31002-M6 2-Port 16Gb Fibre Channel Adapter
81:00.1 Fibre Channel: Emulex Corporation LPe31000/LPe32000 Series 16Gb/32Gb Fibre Channel Adapter (rev 01)
Subsystem: Emulex Corporation LPe31002-M6 2-Port 16Gb Fibre Channel Adapter
By default, these HBA are configured with Point-to-Point (PTP) fibre channel topology. With our direct fibre optical cable between the HBA of the tape server and the tape drive, this needs to be changed to Loop otherwise the tape server can not see the connected tape drives.
To do that Emulex HBA Manager Core Application Kit (CLI) for Linux - RHEL on x86_64 Architecture is needed. At the time of writing this documentation (April 2024) it was available under this link: https://docs.broadcom.com/docs/elx_elxocmcore-rhel8-rhel9-14.2.673.33-1.tgz
From that TAR file, this RPM can be extracted:
-rw-r--r--. 1 root root 1335578 Nov 11 05:58 /root/elxocmcore-rhel8-rhel9-14.2.673.33-1/x86_64/rhel-9/elxocmcorekit-14.2.673.33-1.rhel9.x86_64.rpm
Once this RPM is installed on a given tape server with the Emulex HBA, use this command to see the current topology:
[root@tpsrv601 ~]# for i in $(cat /sys/class/fc_host/*/port_name); do wwn=$(echo ${i:2} | sed -e "s/[0-9A-Fa-f]\{2\}/&:/g" -e "s/:$//"); /opt/emulex/ocmanager/bin/hbacmd getfwparams $wwn; done
FW Params for 10:00:70:b7:e4:15:6d:11
FX Param Low High Def Cur Dyn
00: FA-PWWN 0 1 0 0 5
01: 16G-FEC 0 1 1 1 1
02: DYNAMIC-DPORT 0 1 1 1 1
08: TOPOLOGY 2 3 3 3 5
Param Name Value
FA-PWWN {0=Disable, 1=Enable}
16G-FEC {0=Disable, 1=Enable}
DYNAMIC-DPORT {0=Disable, 1=Enable}
TOPOLOGY {2=Loop, 3=PTP}
FW Params for 10:00:70:b7:e4:15:6d:12
FX Param Low High Def Cur Dyn
00: FA-PWWN 0 1 0 0 5
01: 16G-FEC 0 1 1 1 1
02: DYNAMIC-DPORT 0 1 1 1 1
08: TOPOLOGY 2 3 3 3 5
Param Name Value
FA-PWWN {0=Disable, 1=Enable}
16G-FEC {0=Disable, 1=Enable}
DYNAMIC-DPORT {0=Disable, 1=Enable}
TOPOLOGY {2=Loop, 3=PTP}
Notice the Cur column, the current topology is set to 3=PTP. To set it to 2=Loop, use this command:
[root@tpsrv601 ~]# for i in $(cat /sys/class/fc_host/*/port_name); do wwn=$(echo ${i:2} | sed -e "s/[0-9A-Fa-f]\{2\}/&:/g" -e "s/:$//"); /opt/emulex/ocmanager/bin/hbacmd setfwparam $wwn TOPOLOGY 2; done
Set FW Parameter TOPOLOGY=2 for 10:00:70:b7:e4:15:6d:11
Reset adapter port to activate new firmware parameter setting.
Set FW Parameter TOPOLOGY=2 for 10:00:70:b7:e4:15:6d:12
Reset adapter port to activate new firmware parameter setting.
Once this is done, reboot the tape server and it should now be able to see the connected tape drives.