A loader (also called tape library or autoloader) is a device that consists of drive(s), a magazine with slots for tape cartridges and a robotic mechanism that moves media between the slots and drives. In SEP sesam there is no dependency to use specific manufacturers' devices or device types; you can check the list of supported hardware at Supported Storage Hardware.
SEP sesam can detect and automatically configure storage hardware in your environment if the hardware is supported and recognized by the operating system (it must be listed in the OS device manager), where the SEP sesam Server or Remote Device Server is installed.
During SEP sesam Server installation, SEP sesam checks the SCSI API of the operating system for connected storage devices and puts accessible device files (SCSI address) into the SEP sesam database. This auto-detection works for most devices, but for certain types of loaders the connection between loader and drives cannot be recognized automatically. You have to manually verify and configure such devices. You also have to manually configure any backup device that is connected after SEP sesam installation. Note that the procedure differs depending on your operating system (Linux or Windows).
Automatically detected storage devices
SEP sesam displays automatically detected backup devices in GUI: Main selection -> Components -> Loaders. All detected loaders are displayed; you only need to select a loader to review its properties, and then click OK to confirm the loader configuration.
|It is recommended that SEP sesam auto-configures backup devices, but even for the automatically configured backup devices you should enable persistent naming and check their configuration to configure them as required and avoid errors in SEP sesam operation. See sections Enabling persistent naming for tape devices and Using slu topology for detecting devices.
Preparing loaders and drives
Preparation of storage devices is based on the following general sequence. Note that this sequence might differ for specific devices and might require some additional steps.
- Connect a storage device to SEP sesam Server or SEP sesam Remote Device Server (RDS). Follow the configuration instructions specified by the device vendor or the operating system.
- Install the latest vendor driver for the tape drives, and also the latest driver for the loader. Note that during SEP sesam Server installation SEP sesam will check the SCSI API of the operating system for connected storage devices and enter working device files (SCSI address) into SEP sesam database automatically. Typically, this auto-detection will work for most devices, but there are some exceptions that need manual verification and configuration of the server operating system to allow device discovery.
- Restart the system to ensure that connected storage devices become known to the system.
- Check your device vendor documentation for any additional steps that may have to be performed.
Manually configuring loaders and drives
Checking hardware configuration on Windows
If your loader is detected by SEP sesam automatically, you can skip this step. If you have to add it manually to your Windows system, you must ensure that the hardware is recognized correctly by the operating system in the Windows Device Manager.
- Open Windows Device Manager and check that the selected hardware is present and recognized, as shown in the example below.
- In the Device Manager window, also check that the tape drives have a Tape Symbolic Name displayed.
If it is not recognized, it will be shown with a status Unknown Medium Changer as in the following example.
If it is shown as unknown, right-click it and select Update Driver Software to open the Update Driver Software-Unknown Medium Changer window. Then select or download and install the appropriate driver.
|A wrong driver (or no driver at all) is a common cause of errors. Identify the hardware manufacturer and download the correct driver from their support website to ensure proper configuration of your hardware device. For more information, check the documentation provided by the hardware manufacturer.
Enabling persistent naming for tape devices
Persistent naming or binding is an option that enforces file names for loaders and tape drives, thus making them persist across reboots of the operating system. Without this feature the SCSI addresses may be changed during reboots, especially in environments with several tape libraries attached to a server, and the operating system might mix the SCSI addresses between different loaders and library tape drives. Consequently, SEP sesam may have problems accessing devices, such as unloading incorrect drives, read/open errors, volume errors, lost connections ...
Persistent naming means using symbolic names for loaders, tape drives in autoloaders and tape libraries, as well as for single tape drives. These names stay unique during server reboots, regardless of the order in which the operating system discovers the tape hardware. For example, while Tape0 is a logical name that could change during system restart, the persistent name Tape2147483644 is unique and will not change.
Configuration of persistent naming depends on the used driver. Once OS is configured for persistence naming, update SEP sesam configuration with the help of slu topology.
|Persistent naming is not part of SEP sesam as each hardware vendor handles it differently. If you need any assistance, consult your respective OS and hardware vendor support. The following information are only for reference and are not meant to replace the official vendor documentation.
Configuring persistent naming on Windows
To enable persistent bindings of symbolic tape and library names, you have to modify the registry key. Make sure that you have a valid SEP sesam and operating system backup before proceeding!
- Standard Windows drivers
- For standard Windows drivers, proceed as follows:
- Open Registry Editor: use Start and type regedit.
- Locate and select the following registry subkey:
- From the Edit menu, select New and then DWORD Value.
- Type Persistence and then press ENTER.
- Right-click the Persistence registry entry, then click Modify.
- Type 1 in the Value data box, and then click OK.
- Close Registry Editor and restart the computer.
When you set the Persistence registry entry to 1, symbolic names become persistent. For example, if your tape drive has the name \\.\\tape1, this name is reserved for use by that device even after your server reboots.
- IBM drivers
- For IBM drivers, proceed as follows:
- Go to
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ibmtp2k''<x>''where value <x> in ibmtp2k specifies the Windows Server version, for example, ibmtp2k8 for Windows Server 2008, ibmtp2k12 for Windows 2012, and ibmtp2k16 for Windows 2016, respectively.
- Add DWORD:PersistentNaming=1.
- Close Registry Editor and ensure that AutoRun is set to 0 for the driver prior to rebooting; for details, see official Microsoft documentation, e.g., Windows Server 2003 cannot perform backup jobs to tape devices on a storage area network or refer to the article Disable Autorun/Autoplay.
- Restart the computer.
For more details, see IBM article Configuring drives with persistent naming with IBM devices on Windows.
- HP LTO drivers
- For HP LTO drivers, follow the procedure as provided by data-protector.org:
- Make sure that you have installed the required HP tape drivers.
- Copy the following code and insert it into text editor, then save the content as .reg file.
- Tape drives:
- Execute the .reg file and reboot the Windows system.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\hplto] "AutoRun"=dword:00000000 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Tape] "Persistence"=dword:00000001 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtmsSvc] "Start"=dword:00000004
If you have more than one medium changer include the following two lines as well:
Configuring persistent naming on Linux
Device persistence on Linux is based on preconfigured udev rules. These rules create aliases in the device filesystem in /dev/tape.
Once the persistent naming is configured, you have to identify the WWN of the device and its name. This is because after each reboot on Linux, if you have, for example, two tape drives: /dev/nst0 (typically, the automatically assigned name for the first tape drive on Linux) and /dev/nst1 (the second tape drive), they may be switched around. The device name of a loader may also be changed after reboot. For example, a loader is currently recognized as /dev/sg9, but after reboot its name is changed to /dev/sg6. Changing the device name(s) after each reboot makes it impossible for SEP sesam to recognize the devices without adjustment, causing automated backup processing to fail.
To correctly identify the persistent names of devices on Linux, use the slu scan command and then the /dev/tape/by-id, as shown in the example below.
For example, the slu scan output is as follows:
ID=9:0:9:0 Tape: STK T10000B 0105 (/dev/nst4) ID=9:0:10:0 Tape: STK T10000B 0105 (/dev/nst5) ID=9:0:11:0 Tape: STK T10000B 0105 (/dev/nst6) ID=9:0:12:0 Tape: STK T10000B 0105 (/dev/nst7) ID=9:0:0:0 Loader: STK L700 0105 (/dev/sg17) ID=9:0:8:0 Loader: STK L80 0105 (/dev/sg18)
The output of ls -l /dev/tape/by-id/ shows the following:
total 0 lrwxrwxrwx 1 root root 9 Dec 14 11:17 scsi-350223344ab000900 -> ../../st4 lrwxrwxrwx 1 root root 10 Dec 14 11:17 scsi-350223344ab000900-nst -> ../../nst4 lrwxrwxrwx 1 root root 9 Dec 14 11:17 scsi-350223344ab001000 -> ../../st5 lrwxrwxrwx 1 root root 10 Dec 14 11:17 scsi-350223344ab001000-nst -> ../../nst5 lrwxrwxrwx 1 root root 9 Dec 14 11:17 scsi-350223344ab001100 -> ../../st6 lrwxrwxrwx 1 root root 10 Dec 14 11:17 scsi-350223344ab001100-nst -> ../../nst6 lrwxrwxrwx 1 root root 9 Dec 14 11:17 scsi-350223344ab001200 -> ../../st7 lrwxrwxrwx 1 root root 10 Dec 14 11:17 scsi-350223344ab001200-nst -> ../../nst7 lrwxrwxrwx 1 root root 10 Dec 14 11:17 scsi-SSTK_L700_XYZZY_A -> ../../sg17 lrwxrwxrwx 1 root root 10 Dec 14 11:17 scsi-SSTK_L80_XYZZY_B -> ../../sg18
In our example, by using /dev/tape/by-id/scsi-350223344ab000900-nst instead of /dev/nst4 for the particular drive, the device name will automatically use the correct nst device even after reboot. The same is true for loader names, for example, /dev/tape/by-id/scsi-SSTK_L80_XYZZY_B should be used instead of /dev/sg18.
|Make sure that you use the non-rewind device name nst, in the above example scsi-350223344ab000900-nst, and not the auto rewind version st. If you specify auto rewind version st, a rewind command will be issued to the tape drive and the tape will be positioned at the beginning at the tape. When accessing a non-rewind tape device nst, a rewind command is not issued.
For more details, refer to your hardware manufacturer documentation; for example, IBM article Configuring drives with persistent naming for IBM devices on Linux.
What is next?
Enabling persistent naming is only one step in a sequence for (re-)configuring storage hardware. For full procedure, including using slu topology for identifying the name of the tape hardware and re-configuring loaders and drives, refer to Configuring Loaders and Drives.
Using slu topology for detecting devices
After persistent naming is configured, you have to identify the name of the loader(s) and tape drives and their connection to the SEP sesam internal number of the drive (this drive number is set automatically by SEP sesam) to properly configure devices on the SEP sesam Server.
slu topology is a SEP sesam SCSI loader utility that provides information about the loaders and drives connected to the system; it also shows their relation which is required to identify unique IDs of tape drives and configure them by using SEP sesam GUI.
Using slu topology
- To be able to run the SEP sesam commands globally, you must set up a profile as described in FAQ: What happens when I set a profile?
- To list all attached SCSI devices, run slu topology:
- By examining the output you are able to determine the correct names of loaders and tape drives; in the latter case, you can also determine the connection between the drive name and the drive number sequence. This is important if you are using persistent naming for tape devices. For more details on when to use persistence and how to configure it, see Enabling persistent naming for tape devices. Each tape drive is listed in a separate line with its name (Tapexxx) and its relation to the pre-set drive number in the loader; this pre-set drive number is the last in the line and specifies the number of the tape drive in the loader as referenced by SEP sesam. SEP sesam assigns a number to each tape drive, starting with 0 (0: the first tape drive in the loader; 1: the second tape drive in the loader ...). The equivalent GUI field is named the Drive No. in loader. For example, from the above output you can read the following characteristics that are required for (re-)configuration of loaders and drives in GUI:
- You can also check the number of slots in the loader. SEP sesam numbers the slots from 0 to the number of cartridges in the loader.
If the devices are properly connected, you should get the output similar to the one shown below.
Loader: HP MSL6000 Series 3G3ALRT572VN (Changer0) Drive: HP Ultrium 4-SCSI HU18111L60 ('''Tape2147483644''') (adr=480) '''0''' Drive: HP Ultrium 4-SCSI HU18111L66 ('''Tape2147483643''') (adr=481) '''1''' Drive: HP Ultrium 4-SCSI HU18141PP1 ('''Tape2147483645''') (adr=483) '''3'''
In our example, the tape drive with the persistent name Tape2147483644 relates to drive number 0 (the first tape drive in the loader). You enter the unique tape drive name, e.g., Tape2147483644, when (re)configuring your backup hardware in GUI.
In our example, the loader has 56 slots (0–55) and a port slot which is not configured in SEP sesam.
Now you have all required information to manually (re-)configure your storage hardware.
By using slu topology you can check whether your hardware is properly configured and recognized by SEP sesam. If the device is not listed, SEP sesam auto-detection was not successful. The cause may be trivial, for example, your device driver is not installed correctly. In such cases, you have to install the missing driver and then manually configure your storage hardware. In other rare cases, the connection between loader and drives cannot be recognized automatically and you have to manually configure your storage hardware. For detailed steps on how to manually (re-)confingure your loaders and tape drives, see Configuring Loaders and Drives.
(Re-)Configuring loaders and drives in SEP sesam GUI
These steps differ slightly if you are manually configuring a new device or re-configuring an already existing device. If you are re-configuring an existing device, select it from the list of Loaders and double-click to open the properties and review them, as described in the following steps. Then proceed with re-configuration of drives.
Manually configuring a new loader
- If you are configuring a new device, in SEP sesam GUI from the Main selection -> Components -> Tapes -> Libraries. Click New Loader.
- In the New Loader window, enter its properties which you can read from the output of: <SESAM_BIN>/sesam/slu topology
- Device name: SCSI device filename of the loader. In our Windows example, this is Changer0. On Linux systems it would be, for example, /dev/sg2.
- Device server: SEP sesam Server or Remote Device Server (RDS) to which the loader is connected. In small environments, the loader or disk array is usually installed directly on the SEP sesam Server. More complex backup environments use RDS instead.
- Type: The device type, e.g., LTO4.
- Ctrl : Make sure that DIR_SLU is selected. This is applicable for all loaders which are connected by SAS/iSCSI/FC to the SEP sesam Server or RDS, and provide a robotic control of tape media. (Other options are DIR_VIRT which defines a virtual loader, DIR_DISK which enables controlling a pool of several hard disks, and DIR_ACSLS which defines an ACSLS loader.)
- Slots: Number of slots in the loader.
- Ports: Number of mail slots in the loader.
- Barcode: Depending on whether the loader has a barcode reader or not, select yes or no.
- Auto unload function: Almost all autoloaders and tape libraries allow explicit commands to transport tapes to and from the loader mechanism. It is strongly recommended to disable Auto unload function by setting it to No and allow the manufacturer's drive settings to perform as designed.
Check the output to see if the devices are used correctly by SEP sesam and detect the available SCSI addresses. For details, see above section Using slu topology for detecting devices.
Example of a configured loader
Creating or re-configuring drives
- From the Components, select Tapes and then Drives. In SEP sesam, every drive has to be a member of a drive group. If you have not yet created a drive group, you have to create it now: click the New Drive Group button and enter the name of the new drive group, e.g., Tape_Drives.
- Select the drive group for which you want to (re-)configure the drives, e.g., Tape Drives, and create new drives by clicking New Drive or select existing drives for which you enforced the persistent naming and you have to reconfigure.
- In the New Drive window/Drive properties, the following fields are available:
- Drive number: Number is automatically assigned by SEP sesam; you can change it if you are creating a new drive.
- Drive name: Optionally, enter a description, e.g., logical identifier of a drive.
- Drive type: Select the drive type from the drop-down list of existing drives (LTO, DLT, SLR, etc.)
- Loader: If the drive belongs to the loader, select 1. If it is a single tape drive, select No loader option. (Number 0 defines the virtual loader.) As of 4.4.3 Beefalo V2, you can also select ACSLS, see Configuring ACSLS-Managed Libraries.
- Drive no. in loader: Check the information you got by using slu topology: For example, for the Drive no. in loader with the value 0 you would enter the related persistent name of the drive into the field Device (non-rewinding).
- Device server: The name of the server or RDS to which the drive is connected. The drop-down list displays all available hosts.
- Drive group: Is already selected, based on your previous choice when starting with drive configuration.
- Device (non-rewinding): Based on slu topology output, you have to match the drive's persistent name with the drive number. In our example, for the Drive no. in loader with the value 0 you would insert the persistent drive name Tape2147483644. For details on checking the output, see above section Using slu topology for detecting devices.
- Device Block Size: As of v. 4.4.3 Beefalo V2, it is possible to change the default write density for tapes to achieve better tape performance by using the Device Block Size option. See Setting device block size.
- Tape in drive: If a medium is loaded into the drive, SEP sesam label is displayed.
- Information: If indicated, the messages from the drive hardware are displayed.
- Max. channels: The number of simultaneous backups that can be operated through drives.
- Encryption capable: For already configured drives, it shows whether they are encryption capable. The field is shaded for new drives. Note that SEP sesam provides native support for managing LTO-based encryption; the LTO encryption of tape drives can be enabled on a media pool level. For details, see LTO Encryption.
- Click OK to (re-)configure the drive.
- Repeat the procedure for each drive by entering its persistent name.
|It is recommended to group all drives that belong to the same loader in the same drive group.