ATDD provides the following variety of configurable kernel parameters that allow the users to customize for specific setup:
v atdd_log_trace
Log the sense data in syslog when a hardware or medium error is occurred, see “Sense Data Logging” on page 86 for additional details. This parameter is enabled by default on 11i v3 and later, but disabled by default in 11iv3 and earlier.
v alternate_pathing/atdd_alternate_pathing
Enable or disable the alternate path support for CPF/DPF (see the specific operating system section that covers CPF and DPF support for detail). This parameter is enabled by default.
v atdd_disable_reserve/atdd_disable_res
Allows the user to disable the reservation management from ATDD. This parameter off by default.
v atdd_loadbalance
Allows the user to disable automatic load balancing from ATDD. This parameter is On (1) by default and supported on 11iv3 only
v atdd_reserve_type
The drive is reserved in the SCSI-2 Reserve command when Data Path Failover (DPF) is disabled by default. To reserve the drive using Persistent Reserve In and Out commands, the user can set the value of atdd_reserve_type to 3. The default value for the tunable: 1 - Reserve(6) command; 2 - Reserve(10) command (Unsupported); 3 - Persistent Reserve In/Out commands
To change the value of tunable, run the commandkctune/kmtuneor SAM (System Administration Manager) tool.
Special Files
For each drive configured by ATDD, twelve or thirteen special files are created: twelve special files are generated for a 3590 with ACF set toManual,Automatic, System,Accumulate,Random, orLibrary mode. A thirteenth special file is created for independent operation of the ACF, if the 3590 mode is set to Random 2 LUN operation (/dev/rmt/<instance#>chng).
ATDD creates the tape device special files in three forms: the standard or long file name, an alternative short file name based on the instance number, and an
alternative short file name notbased on the instance number. BEST represents the operational capabilities likely to be required, including the highest density/format and data compression, if supported by the device. Each set of special file names (long and short) contains four special files that have all combinations of nandb options, as shown in Table 11 and Table 12. For more information, refer to the mt(7) man pages.
Table 11. Special Files
Special File Name
BSD Compatibility
Rewind on Close
/dev/rmt/<instance#>m No Yes
/dev/rmt/<instance#>mb Yes Yes
/dev/rmt/<instance#>mn No No
/dev/rmt/<instance#>mnb Yes No
/dev/rmt/s<#>m No Yes
/dev/rmt/s<#>mb Yes Yes
/dev/rmt/s<#>mn No No
/dev/rmt/s<#>mnb Yes No
/dev/rmt/<instance#>t<target>d<LUN>BEST No Yes /dev/rmt/<instance#>t<target>d<LUN>BESTb Yes Yes /dev/rmt/<instance#>t<target>d<LUN>BESTn No No /dev/rmt/<instance#>t<target>d<LUN>BESTnb Yes No
/dev/rmt/<instance#>chng N/A N/A
Table 12. New Special Files in HP-UX 11i v3
Special File Name
BSD Compatibility
Rewind on Close
/dev/rtape/tape#_BEST No Yes
/dev/rtape/tape#_BESTb Yes Yes
/dev/rtape/tape#_BESTn No No
/dev/rtape/tape#_BESTnb Yes No
/dev/rchgr/autoch# N/A N/A
v In HP-UX 11.0, 11i v1 and v2:
atdd_lssfin/opt/OMImag/binfor the static driver and in/opt/atdd/binfor the DLKM driver lists information about a special file. For example:
#atdd_lssf /dev/rmt/393mnb
atdd card instance 30 available at address Major = 79 Minor = Ox1E90C0 settings = No Rewind, Berkeley, Best Format,
IBM 03590H1A /dev/rmt/393mnb v In HP-UX 11i v3:
ATDD supports the HP-UXlssf,insfand rmsfcommands. To display special file information, enter thelssfcommand. For example,
# lssf /dev/rtape/tape14_BESTnb
atdd Berkeley No-Rewind best density available at address 64000/0xfa00/0x32 /dev/rtape/tape14_BESTnb
# lssf /dev/rchgr/autoch1
acdd section 0 at address 64000/0xfa00/0x21 /dev/rchgr/autoch1
If the device special files are not created on the system, use the# insfcommand to generate them.
Persistent Naming Support
Persistent naming support is used to ensure that attached devices are always configured with the same logical name across system reboots. For this purpose, the HP-UX tape driver creates an additional set of device special files with a prefix of “s” for the configured tape drives in HP-UX 11.0, 11i v1 and v2, such as s55m in the following example.
# ioscan -funC tape
Class I H/W Path Driver S/W State H/W Type Description
===================================================================================
tape 103 1/0/0/0.97.25.255.2.7.0 atdd CLAIMED DEVICE IBM 03592E05
/dev/rmt/103m /dev/rmt/c10t7d0BESTn /dev/rmt/s55mb
/dev/rmt/103mb /dev/rmt/c10t7d0BEST /dev/rmt/s55mn
/dev/rmt/103mn /dev/rmt/c10t7d0BESTb /dev/rmt/s55m
/dev/rmt/103mnb /dev/rmt/c10t7d0BESTnb /dev/rmt/s55mnb
In HP-UX 11i v3, HP introduces the native multi-pathing and path-independent persistent Device Special Files (DSFs) and the auto discovery of devices greatly to enhance the overall manageability. The ATDD does not create the additional set of device special files with a prefix of “s”.
The persistent DSF format for tape devices introduced with the Agile view in HP-UX 11i v3 is:
# ioscan -funNC tape
Class I H/W Path Driver S/W State H/W Type Description
===================================================================
tape 1 64000/0xfa00/0x7 estape CLAIMED DEVICE IBM 03592E05
/dev/rtape/tape1_BEST /dev/rtape/tape1_BESTn /dev/rtape/tape1_BESTb /dev/rtape/tape1_BESTnb # ioscan -funNC autoch
Class I H/W Path Driver S/W State H/W Type Description
=================================================================
autoch 8 64000/0xfa00/0xa acdd CLAIMED DEVICE IBM 03584L22
/dev/rchgr/autoch8
To map a persistent DSF to its legacy DSF, enter the following: # ioscan -m dsf /dev/rtape/tape1_BESTb
Persistent DSF Legacy DSF(s)
======================================== /dev/rtape/tape1_BESTb /dev/rmt/c3t15d0BESTb