c01627023

HP Tru64 UNIX - V5.1B-4 Potential Tape Rewind Problem When Using No-Rewind Device

»

HP Tru64 UNIX

Tru64 UNIX

» Tru64 UNIX V5.1B-6
» Tru64 UNIX V5.1B-5
» Documentation
» Information library
» Software web index
» Software products library
» Patch database
» Services
» Developer & Solution Partner Program
» Send us your comments
» Support Statements

Evolving business value

» Tru64 UNIX to HP-UX 11i transition benefits calculator
» Alpha RetainTrust Program
» Transition

Related links

» Alpha systems
» HP-UX 11i
» Integrity servers
» Linux
» HP storage
» HP solutions
HP-UX 11i: measurably better TCO!
 Advisory Information
 

LAST UPDATE: 2008-12-18

DESCRIPTION
Tape drives being used with the HP Tru64 Unix V5.1B-4 tape driver and no-rewind tape special device files can rewind between writing files, resulting in overwriting files or save sets that were previously written to the tape. The problem will only occur on tape drives that declare support for asymmetric logical unit access (ALUA) while the cam_ccfg_aa_enable sysconfig variable is set to its default value of 1, for example on HP Ultrium-4 drives.

To determine if this issue might arise, you can examine the returned SCSI INQUIRY data via the scu command.

# scu
scu> sbtl 3 13 0 .................... << set the bus target lun to point to the tape drive
Device: Ultrium 4-SCSI, Bus: 3, Target: 13, Lun: 0, Type: Sequential Access
scu> show inquiry

Inquiry Information:

Peripheral Device Type: 0x1 (Sequential Access)
Peripheral Qualifier: 0 (Peripheral Device Connected)
Device Type Modifier: 0
Removable Media: Yes
ANSI Version: 5 (Reserved)
ECMA Version: 0
ISO Version: 0
Response Data Format: 2 (SCSI-2)
Terminate I/O Process: No
Additional Length: 91
Reserved (byte 5): 0x10 .................... << a non-zero value indicates ALUA supported.
Reserved (byte 6): 0x90
Soft Reset Support: No
Command Queuing Support: No
Target Transfer Disable: No
Linked Command Support: No
Synchronous Data Transfers: No
Support for 16 Bit Transfers: No
Support for 32 Bit Transfers: No
Relative Addressing Support: No
Vendor Identification: HP
Product Identification: Ultrium 4-SCSI
Firmware Revision Level: H44W
Vendor Specific Data:

00 00 00 00 01 3c 0d 00 " . . < . "
00 00 00 00 00 00 00 00 " . . . . "
00 00 00 00 00 00 00 5c " . . . \ "
09 17 0d 7d 0d bc 13 1c " . { . . "
13 3c 03 14 03 7d 00 00 " < . } . "
00 00 00 00 00 00 00 00 " . . . . "
00 00 00 00 00 00 00 00 " . . . . "
00 00 00 00 " . . "

scu>

If "Reserved (byte 5)" is not listed in the INQUIRY output, then the byte value is 0x00 and ALUA is not supported.

Another more direct method can be used by writing two files to the no-rewind tape device to be checked. This should be run only after making sure the sysconfig option 'cam_ccfg_aa_enable' is set to its default value of '1'. If not, set the value to '1' for testing and then switch it back after testing is complete.

-- File: tar_test --
#/bin/ksh
echo Test Passed > file1_temp_tar_test
echo Test Failed > file2_temp_tar_test

mt -f ${1} rewind
tar -cvf ${1} file1_temp_tar_test
tar -cvf ${1} file2_temp_tar_test
mt -f ${1} rewind

rm *temp_tar_test
tar -xvf ${1}
cat *temp_tar_test
-- EOF --

# sysconfig -q cam cam_ccfg_aa_enable
cam:
cam_ccfg_aa_enable = 1
# tar_test /dev/ntape/tape5c
a file1_temp_tar_test 1 Blocks
a file2_temp_tar_test 1 Blocks
blocksize = 20
x file1_temp_tar_test, 12 bytes, 1 tape blocks
Test Failed

Tape drives with which this issue will arise will echo 'Test Failed'.
 

SCOPE
This issue arises only when using Tru64 Unix/TruCluster V5.1B-4 with tape drives that support the ALUA feature.
 
RESOLUTION

HP is releasing the following ERP kit publicly for use by any customer. The ERP kit uses dupatch to install and will not install over any Customer Specific Patches (CSPs) that have file intersections with the ERP. Contact your service provider for assistance if the installation of an ERP is blocked by any of your installed CSPs.

The fixes contained in the ERP kits are scheduled to be available in the following mainstream patch kit: HP Tru64 UNIX V5.1B-5

Downloadable Solution

Product: HP Tru64 UNIX version: 5.1B-4
Downloadable File: T64KIT1001568-V51BB27-E-20081211.tar
Kit Location:
http://www.itrc.hp.com/service/patch/patchDetail.do?patchid=T64KIT1001568-V51BB27-E-20081211

NOTE: Until the ERP is installed, customers should use the following workaround to prevent the issue from arising:

Disable the sysconfig variable 'cam_ccfg_aa_enable' during tape use as follows:

  1. Disable sysconfig variable using following command.
    # sysconfig -r cam cam_ccfg_aa_enable=0

  2. Utilize tapes for backup operations, etc.

  3. Enable sysconfig variable using following command after backups complete.
    # sysconfig -r cam cam_ccfg_aa_enable=1