Re: Disabled hw compression
Joshua Baker-LePain wrote: On Mon, 17 Feb 2003 at 11:27pm, [EMAIL PROTECTED] wrote I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? For that drive, compression is controlled via density. 0x15 is uncompressed. The latest amtapetype from amanda 2.4.4b1 includes an heuristic test to check if the tapedrive really has hardware compression disabled (it could be on because dipswitches were set to force it on or off regardless of software commands). Run it as amtapetype -c ... to do the compression detection test only (the tape contents are lost; use a scratch tape!). Paul
Re: Disabled hw compression
On Tuesday 18 February 2003 05:44 am, Paul Bijnens wrote: Joshua Baker-LePain wrote: On Mon, 17 Feb 2003 at 11:27pm, [EMAIL PROTECTED] wrote I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? For that drive, compression is controlled via density. 0x15 is uncompressed. The latest amtapetype from amanda 2.4.4b1 includes an heuristic test to check if the tapedrive really has hardware compression disabled (it could be on because dipswitches were set to force it on or off regardless of software commands). Run it as amtapetype -c ... to do the compression detection test only (the tape contents are lost; use a scratch tape!). Paul There is also a util called tapeinfo which I believe is part of the current mtx package. It reports on the complete device, non-destructively. To use it, you give it the 'sg' address of the drive in the changer, like this: [amanda@coyote everything]$ tapeinfo -f /dev/sg0 Product Type: Tape Drive Vendor ID: 'ARCHIVE ' Product ID: '4586XX 28887-XXX' Revision: '0420' Attached Changer: No SerialNumber: 'DT014WP' MinBlock:1 MaxBlock:16777215 SCSI ID: 6 SCSI LUN: 0 Ready: yes BufferedMode: yes Medium Type: 0x32 Density Code: 0x24 BlockSize: 512 DataCompEnabled: no DataCompCapable: yes DataDeCompEnabled: yes CompType: 0x0 DeCompType: 0x0 Block Position: 64 -- I have no idea why it says there is no attached changer, because it has one at LUN=1. But the data is otherwise accurate. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.23% setiathome rank, not too shabby for a WV hillbilly
Re: Disabled hw compression
Under Linux you can call the following to disable compression. mt -f /dev/st0 nocompression The other method would be the disable a DIP switch or jumper on the tape drive. I include the above line in my startup scripts. It would appear it only needs to be set at boot. Russell On Mon, Feb 17, 2003 at 11:27:11PM +0100, [EMAIL PROTECTED] wrote: Hello, I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? Thanks Regards
Re: Disabled hw compression
On Tue, Feb 18, 2003 at 10:23:01AM +0100, [EMAIL PROTECTED] wrote: On Mon, Feb 17, 2003 at 05:51:16PM -0500, Joshua Baker-LePain wrote: On Mon, 17 Feb 2003 at 11:27pm, [EMAIL PROTECTED] wrote I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? For that drive, compression is controlled via density. 0x15 is uncompressed. Isn't there a generic way of configuring it, like /dev/nst0 is the Simple answer is NO, there is no generic way. Case in point, my drive has internal dip switches that if I set them in various configs will totally disable HW compression or will force HW compression on with no ability to change it except reset the switches and power cycle. I have elected to set those switches to power up in no compression, software selectable. But another site might choose differently. non-rewinding device, isn't there a non compressing device? (I have the same question actually about being sure a Dell tape is in non compressing config, but I don't have the complete model details at hand) Some OS's do use different devices to select compression. I do not think those that use nst# and st# device names use that scheme. Instead they have software to set device properties, generally the mt command. Again, no generic solution there. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road(609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)
Re: Disabled hw compression
Just for your information, on my Linux mtx's version (Slackware 8.1 with a 2.4.18 kernel) there is no such option nocompression to mtx... But there are the options defcompression and compression which can be set to 0 then it looks like that compression is disabled... PS: thanks Joshua for your help Regards Russell Adams To: [EMAIL PROTECTED] RLAdams@kelsey-sey cc: bold.com Subject: Re: Disabled hw compression Sent by: owner-amanda-users@ amanda.org 02/18/03 04:54 PM Under Linux you can call the following to disable compression. mt -f /dev/st0 nocompression The other method would be the disable a DIP switch or jumper on the tape drive. I include the above line in my startup scripts. It would appear it only needs to be set at boot. Russell On Mon, Feb 17, 2003 at 11:27:11PM +0100, [EMAIL PROTECTED] wrote: Hello, I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? Thanks Regards
Re: Disabled hw compression
My bad, I was having an OpenVMS moment. :P Its really... mt -f /dev/st0 compression off Russell On Tue, Feb 18, 2003 at 05:52:44PM +0100, [EMAIL PROTECTED] wrote: Just for your information, on my Linux mtx's version (Slackware 8.1 with a 2.4.18 kernel) there is no such option nocompression to mtx... But there are the options defcompression and compression which can be set to 0 then it looks like that compression is disabled... PS: thanks Joshua for your help Regards Russell Adams To: [EMAIL PROTECTED] RLAdams@kelsey-sey cc: bold.com Subject: Re: Disabled hw compression Sent by: owner-amanda-users@ amanda.org 02/18/03 04:54 PM Under Linux you can call the following to disable compression. mt -f /dev/st0 nocompression The other method would be the disable a DIP switch or jumper on the tape drive. I include the above line in my startup scripts. It would appear it only needs to be set at boot. Russell On Mon, Feb 17, 2003 at 11:27:11PM +0100, [EMAIL PROTECTED] wrote: Hello, I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? Thanks Regards
Re: Disabled hw compression
On Tue, Feb 18, 2003 at 11:00:26AM -0600, Russell Adams wrote: My bad, I was having an OpenVMS moment. :P Its really... mt -f /dev/st0 compression off I don't have this either; I only have (from the manpage) a datcompression that take 1(show) , 0 (disables) or nothing (enables) as argument. mt -f /dev/st0 datcompression 0 has worked as wanted (tapeinfo is showing the change). Raph -- Free and Open Source Developers' European Meeting http://www.fosdem.org
Re: Disabled hw compression
On Tuesday 18 February 2003 02:41 pm, [EMAIL PROTECTED] wrote: On Tue, Feb 18, 2003 at 11:00:26AM -0600, Russell Adams wrote: My bad, I was having an OpenVMS moment. :P Its really... mt -f /dev/st0 compression off I don't have this either; I only have (from the manpage) a datcompression that take 1(show) , 0 (disables) or nothing (enables) as argument. mt -f /dev/st0 datcompression 0 has worked as wanted (tapeinfo is showing the change). A Side comment here in case the mt folks are watching. I would be VERY nice if mt had the same syntax across all the platforms it runs on. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.23% setiathome rank, not too shabby for a WV hillbilly
Re: Disabled hw compression
On Tuesday 18 February 2003 20:42, Gene Heskett wrote: mt -f /dev/st0 datcompression 0 has worked as wanted (tapeinfo is showing the change). A Side comment here in case the mt folks are watching. I would be VERY nice if mt had the same syntax across all the platforms it runs on. But there are no mt folks - that's the problem. mt is an old program, and there are many versions of it, many of which have different implementors - why, even amanda has its own version of mt now. And unfortunately, these implementors had different idea about the functionality they would add to mt, and even about the names they would give to those functionalities. Kindest regards, Niall O Broin
Disabled hw compression
Hello, I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? Thanks Regards
Re: Disabled hw compression
On Mon, 17 Feb 2003 at 11:27pm, [EMAIL PROTECTED] wrote I am using an Exabyte Eliant 820 tape drive on Linux kernel 2.4.18 and would like to make sure the hardware compression is disabled. Does anyone know how I can check that ? For that drive, compression is controlled via density. 0x15 is uncompressed. -- Joshua Baker-LePain Department of Biomedical Engineering Duke University
