sandman Posted October 2, 2002 Report Share Posted October 2, 2002 how do i turn hardware compression on in retrospect? setting the option in the backup set config doesn't seem to do it. the middle light on my drive should change to amber when it is in compression mode, but it is not. I manually set the compression mode 'on' on the tape drive with an external app, but it seems to have been turned off by retrospect. I tried formatting the tape with the 8500c format, still no luck. i am using sony 160m tapes which should support compression mode Link to comment Share on other sites More sharing options...
AmyJ Posted October 2, 2002 Report Share Posted October 2, 2002 When making a tape backup set, hardware data compression is "on" by default. Get properties on your backup set (Configure > Backup Sets > Properties) to determine if hardware compression is enabled. These options cannot be changed once a backup set has been created. As a test, you can create a new tape backup set, and turn off the option for hardware compression in the backup set creation window. Run a backup with software data compression enabled. Are you able to fit more on your media? If so, your tape drive is having a problem compressing data. Retrospect sends the data to the drive, and it is up to the drive to compress the data. Retrospect cannot enable or disable compression on a hardware device. If you determine that your tape drive is not compressing data, you should contact the hardware vendor. The following knowledgebase article may help in better understanding tape capacity and compression: The following Knowledgebase articles will fully explain the capacity issues you are experiencing: Tape Capacity FAQ Link to comment Share on other sites More sharing options...
sandman Posted October 2, 2002 Author Report Share Posted October 2, 2002 very interesting, "Retrospect cannot enable or disable compression on a hardware device." I would have thought this was what the hw comp setting did when one created a new backup setup. I did run a sw compression job on a new backup set and got 4% compression, but capacity is not my main concern right now. My real problem is how to set compression 'on' for my tape drive. it seems to keep getting turned off. when I format an 8mm tape with the 8500c format, does this signal the device (exabyte 8505xl) to turn hw comp on? does version 6.0 enable or disable hw comp on devices? thanks Link to comment Share on other sites More sharing options...
AmyJ Posted October 2, 2002 Report Share Posted October 2, 2002 In reply to: I manually set the compression mode 'on' on the tape drive with an external app What application are you using? Is it supported by the hardware vendor? Hardware compression is generally toggled on the device itself, and not through a software package. In reply to: I tried formatting the tape with the 8500c format, still no luck. Have you tried a new tape, or all they all previously used tapes? Link to comment Share on other sites More sharing options...
sandman Posted October 3, 2002 Author Report Share Posted October 3, 2002 doesn't the selection of the tape format I choose (8200, 8200c, 8500, or 8500c from Retrospect for my exabyte 8505xl) determine if compression is enabled or disabled? That is, if I format a tape with 8500c, doesn't the new formatted tape signal the drive to use hw comp. regarding your questions: the software is from the exabyte (called Expert 7.4). there are no btns on the tape drive to select density or compression. I have tried new and used tapes (112m & 160m), and can't seem to find a pattern. Link to comment Share on other sites More sharing options...
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