09/24/96, Incompatible Block Sizes for AIX 3.1 SPECIAL NOTICES Information in this document is correct to the best of our knowledge at the time of this writing. Please send feedback by fax to "AIXServ Information" at (512) 823-4009. Please use this information with care. IBM will not be responsible for damages of any kind resulting from its use. The use of this information is the sole responsibility of the customer and depends on the customer's ability to eval- uate and integrate this information into the customer's operational environment. +----------------------------------------------------------+ | | | NOTE: The information in this document has NOT been | | verified for AIX 4.1. | | | +----------------------------------------------------------+ ABOUT THIS DOCUMENT This document contains steps to the resolution to the problem and cause of backup tape block size and is appli- cable to AIX 3.1. PROBLEM: Backup tape was made with block size set to 512. When the user tried to restore the tape from the install diskettes, the block size was set to 1024. The machine gave a read error when it tried to read the tape. CAUSE: These block sizes are inconsistent because the information is taken from two different places. When the tape is made up, the block size is taken from the ODM (CuAt specif- ically). When the tape is restored, the block size is taken from the install diskette. RESOLUTION (FOR AIX 3.1 ONLY): To solve the problem, change the block size that the install diskette uses. To do this, use the following procedure: 1. Enter: "mkdir /tmp/inst" to create a temporary directory. 2. Enter: "cp /etc/objrepos/boot/mediadd.bff /etc/objrepos/boot/mediadd.bffold" Incompatible Block Sizes for AIX 3.1 1 09/24/96, to create a backup of mediadd.bff. 3. Enter: "cp /etc/objrepos/boot/mediadd.bff /tmp/inst" This puts the file in the temporary directory so we can play with it. 4. Enter: "cd /tmp/inst" 5. Enter: "restore -xvqf mediadd.bff" The files which are restored are basically the ODM which is used by the install process. | 6. Enter: | "vi scsidev.add" Search on "block_size". The cursor should be on "attri- bute = block_size". The line above the cursor should read "uniquetype = tape/scsi/8mm" and the line below "deflt = 1024". Cursor down one line to "deflt = 1024" and change the 1024 to 512. Save the file. 7. Enter: "rm mediadd.bff" so that the file isn't backed up by the next command. 8. Enter: "ls | backup -ivqf mediadd.bff" to put the files back into the backup file. 9. Enter: "cp mediadd.bff /etc/objrepos/boot" 10. Enter: "/usr/lpp/bosinst/diskette/mkinstdskt /usr/bin/bosinst.image" to make the install image. 11. Enter: "dd if=/usr/bin/bosinst.image of=/dev/rdf0" to put the install image on diskette. Incompatible Block Sizes for AIX 3.1 2 09/24/96, 12. Boot up using this new diskette as the installation disk. Incompatible Block Sizes for AIX 3.1 3 09/24/96, READER'S COMMENTS Please fax this form to (512) 823-4009, attention "AIXServ Informa- tion". You may also e-mail comments to: elizabet@austin.ibm.com. These comments should include the same customer information requested below. Use this form to tell us what you think about this document. If you have found errors in it, or if you want to express your opinion about it (such as organization, subject matter, appearance) or make sug- gestions for improvement, this is the form to use. If you need technical assistance, contact your local branch office, point of sale, or 1-800-CALL-AIX (for information about support offer- ings). These services may be billable. Faxes on a variety of sub- jects may be ordered free of charge from 1-800-IBM-4FAX. Outside the U.S. call 415-855-4329 using a fax machine phone. 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