| StorageTek SL150 Modular Tape Library Systems Assurance Guide 22579-04 |
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| StorageTek SL150 Modular Tape Library Systems Assurance Guide 22579-04 |
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This chapter provides information for consideration when planning for the installation of the StorageTek SL150 Modular Tape Library.
The SL150 Modular Tape Library uses a single SCSI ID and two logical unit numbers (LUN). LUN 0 controls the tape drive and LUN 1 controls the robotics. The tape drives in the base module provide the bridging function and must be connected to an HBA supporting multiple LUNs (also referred to as LUN scanning).
Make sure that the proper device driver is installed, if applicable. Download the driver from the HP web site, if needed.
For example, Oracle has qualified the HP LTO-5 and LTO-6 drives with Windows driver 3.5.0.0.
The library can be connected to the host HBA through a storage area network (SAN). Configure zoning on the Fibre Channel switch so only the backup servers access the library.
The half-height FC tape drive has an 8 Gb/s data interface.
When a server is booted, devices are discovered and assigned SCSI target and LUN IDs. It is possible for these SCSI assignments to change between boots. Some operating systems do not guarantee that devices will always be allocated the same SCSI target ID after rebooting. Also, some software depends on this association, so yo do not want it the change. The issue of SCSI ID assignment is addressed by persistent binding.
Persistent binding is a host bus adapter (HBA) function that allows a subset of discovered targets to be bound between a server and device.
Implemented by a World Wide Node Name (WWNN) or World Wide Port Name (WWPN), persistent binding causes a tape drive's World Wide Name to be bound to a specific SCSI target ID.
Zoning allows you to partition your SAN into logical groupings of devices so that each group is isolated from the other and can only access the devices in its own group. Two types of zoning exist:
Hardware zoning: based on physical fabric port number
Software zoning: defined with the World Wide Node Name or World Wide Port Name
While zoning can be re-configured without causing an outage, some zoning configurations can become complicated. The advantage of the library's WWNN implementation is that you can avoid the exposure of introducing zoning errors because there is no need to change the zoning configuration is a drive needs service or replacement.
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Note: The dynamic World Wide Name (dWWN) feature assigns world wide names to the library drive slots rather than the drives themselves which allows you to swap or replace a drive without bringing down the entire operating system. |
SAS uses serial connections, with a direct connection between the host server and each of the storage devices. SAS signal rates require clean connections and a minimum number of connections between the HBA and the SL150 Library. Oracle recommends a maximum SAS cable length of six meters.
The half-height SAS tape drive has a 6 Gb/s data interface.
Oracle SAS HBAs:
3Gb (SAS-1):
SG-XPCI8SAS-E-Z
SG-XPCIE8SAS-E-Z
SG-XPCIE8SAS-EB-Z
6Gb (SAS-2):
SGX-SAS6-EXT-Z
SGX-SAS6-EM-Z
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Caution: The Solaris 10 (Update 8 and later) SAS driver disrupts communications between Oracle Solaris and common tape backup applications. |
The SAS driver only allows one device driver to attach per device (sg, sgen, st, and so forth). Users must have every component in the following list to be affected:
Oracle Solaris 10 (Update 8 or later) or Solaris 11
Any SAS-2 HBA
Tape drives or libraries using a SAS-2 connection
A backup application that requires multiple SAS drivers. The most common backup applications that use multiple device drivers include:
CA ARCserve
EMC Networker
HP Data Protector
IBM Tivoli Storage
Symantec NetBackup
A SAS tape drive attached through the SAS-2 HBA will work on the Solaris system using just the Solaris native commands such as dd or tar.
The front and rear service clearance must be at least 965 mm (38 inches).
When a tape drive has two ports, host applications can treat the second drive port as a failover port. The library may report a Check Condition to a command received on one port when the other port is busy with a library command. When a host application receives either of the following new Check Conditions, it should reissue the command:
Not Ready, Logical Unit Offline (02/04/12h)
Aborted Command, Logical Unit Communication Failure (OBh/08/00)
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Notes: The half-height LTO-5 FC tape drive has one port while the other supported drives have two ports.Only some host applications support this feature. Be sure to check the status of this feature with your application. |
LTO drives send a cleaning request to the SL150 and the host application managing the library (or partition). You can handle cleaning in either of two ways:
Automatically manage cleaning by configuring the host application (for example, Symantec NetBackup or IBM Tivoli Storage Manager) for Automatic, Tape Alert, or reactive cleaning depending on the application.
Monitor the library health for a Degraded state and initiate cleaning for the specific drive. Because this is not an automatic process, you must monitor drives regularly and respond quickly to cleaning requests.
Refer to the StorageTek SL150 Modular Tape Library User's Guide for details on implementing tape drive cleaning.
