Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!uwm.edu!linac!mp.cs.niu.edu!ux1.cso.uiuc.edu!shair From: shair@ux1.cso.uiuc.edu (Bob Shair) Newsgroups: comp.unix.aix Subject: Re: "rdump" only writes half as much data as "backup" Message-ID: <1991Jun13.045554.18719@ux1.cso.uiuc.edu> Date: 13 Jun 91 04:55:54 GMT References: Organization: University of Illinois at Urbana Lines: 65 henkel%nepjt@ncsuvx.ncsu.edu (Chuck Henkel) writes: >Context: Two RS/6000 Model 320s running 3001. > Tape drive configured for 512 byte blocks, no ECC >I'm trying to use rdump to back up a filesystem on "rs1" to a >cartridge tape on "rs2": >rdump -0 -c -f rs2:/dev/rmt0.4 /u >only writes about 10 meg on the tape, then asks for another. If I use >a high density tape, (3M 6150, /dev/rmt0), it only puts about 20 meg >on the tape, then asks for another. >The "-b" flag (blocksize) has no apparent effect. Backing up >filesystems on rs2 (the machine with the tape) works fine. >What's the deal? The deal is we accidentally omitted the -d (density) and -s (size) flags from the man pages for rdump when we shipped AIX 3.1; they're in updated versions. For a DC600A 120MB tape (rmt0.4) specify -s 9000 -d 1250 I append the appropriate Flags from 3.1.5 manual. rdump Command Syntax rdump [ -b Number1 ] [ -c] [ -d Number2 ] [ -l Number3 ] [-s Number4 ] [ -u] [ -w] [ -W] [ -Level] -f Machine:Device [ FileSystem] Flags -b Number1 Specifies the number of blocks to write in a single output operation. If you do not specify the Number1 parameter, the rdump command uses a default value appropriate for the physi- cal device selected. Larger values of the Number1 parameter, result in larger physical transfers to tape devices. -c Specifies that the tape is cartridge, not nine-track. -d Number2 Specifies the density of the tape in bits per inch (BPI). This value is used in calculating the amount of tape used per volume. If you do not specify a value for the Number2 parameter, the rdump command uses a default density of 1600 BPI. For a default density of 8000 BPI, specify the -c flag. -l Number3 Uses the Number3 parameter as the limit of the total number of blocks to use on the remote backup medium. -s Number4 Allows you to specify the size of the tape in feet us- ing the Number4 parameter. If you do not specify a tape size, rdump defaults to a tape size of 2300 feet. For a de- fault size of 1700 feet, use the -c flag. When the tape drive reaches the specified size, the rdump command waits for the tape to be changed. -- Bob Shair shair@chgvmic1.vnet.ibm.com Scientific Computing Specialist SHAIR@UIUCVMD (bitnet) IBM Champaign