Re: Tape parameters for dump
I wrote earlier asking for help using dump with a DAT drive, and I received replies from Steven W Orr [EMAIL PROTECTED] and [EMAIL PROTECTED] I just wanted to thank them both for their helpful responses. To sum up, setting the -s option to a large enough number will let dump think that the tape is long enough to accommodate the dump, even with the other tape characteristics set to thier defaults. To find the exact number will take some experimenting, but I have the idea now anyway. FYI, Steve and Ken, my 90-meter tape "stretched" to 12 feet (!) and fit about 1.8 Meg without running off the end. Matthew Saltzman Clemson University Math Sciences [EMAIL PROTECTED] http://www.math.clemson.edu/~mjs -- To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject.
Re: Tape parameters for dump
I went through this problem a while ago. Turns out that the DAT drives are helical. This means that the *effective* length of the tape is calculated based on the density of a helical stripe on the tape multiplied by the number of stripes that fit on the tape. [What the hell is he talking about?] The practical solution is to run your dump with a tape length set to something like 67000 meters. Maybe less for a 90 m tape, but that's the sort of number I use for a 120. Sorry I don't have the exact number on me, as my 'puter is at home. -- --Time flies like the wind. Fruit flies like a banana. Stranger things have happened but none stranger than this.- Steven W. Orr [EMAIL PROTECTED] site of former bang addr:-) ---"Listen to me! We are all individuals."- On Tue, 4 Jan 2000, Matthew Saltzman wrote: =Backup gurus- = =I was trying to use dump for a rudimentary backup with a 4mm DAT =drive. The drive capacity is 4-8G and the tape capacity is 2-4G (90 =meters, I believe). I have about 1-2G to back up. But if I run dump =with the default settings, only a small amount of data is written =before dump requests a new volume. = =So my question is: What are the right settings for the dump parameters =-B (records), -b (blocksize), -d (density), and/or -s (feet) for this =configuration? (Also, am I correct in assuming that this has nothing =to do with the drive capacity and everything to do with the tape =capacity?) -- To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject.
Re: Tape parameters for dump
I went through this problem a while ago. Turns out that the DAT drives are helical. This means that the *effective* length of the tape is calculated based on the density of a helical stripe on the tape multiplied by the number of stripes that fit on the tape. [What the hell is he talking about?] What he's saying is that the 4 8mm drives work like a VHS VCR. the read write heads *fly* across the tape diagonally instead of along its length (like a cassette, remeber those?) which means that he calculated the *length* of the tape as far as dump is concerned as being the physical length of the tape (90 or 120 meters) times the width of the tape (4 or 8 mm) divided by the width of the tracks --- a cassette records as follows a helical recordslike this so for the same physical length of tape you get more data on the tape. I'm sure that is clear as mud but... I tried -- Ken -- To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject.
Re: Tape parameters for dump
[EMAIL PROTECTED] wrote: I went through this problem a while ago. Turns out that the DAT drives are helical. This means that the *effective* length of the tape is calculated based on the density of a helical stripe on the tape multiplied by the number of stripes that fit on the tape. I think this may only be true for MRS tapes (media regognition system) tapes. There are also tapes that don't have the MRS diagonal marks that do work as well. [What the hell is he talking about?] What he's saying is that the 4 8mm drives work like a VHS VCR. the read write heads *fly* across the tape diagonally instead of along its length (like a cassette, remeber those?) which means that he calculated the *length* of the tape as far as dump is concerned as being the physical length of the tape (90 or 120 meters) times the width of the tape (4 or 8 mm) divided by the width of the tracks --- a cassette records as follows a helical recordslike this so for the same physical length of tape you get more data on the tape. I'm sure that is clear as mud but... I tried -- Ken -- To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject. -- Bruce Kall Mayo Foundation Rochester, MN e-mail: [EMAIL PROTECTED] phone: (507) 255-4768 -- To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject.
Tape parameters for dump
Backup gurus- I was trying to use dump for a rudimentary backup with a 4mm DAT drive. The drive capacity is 4-8G and the tape capacity is 2-4G (90 meters, I believe). I have about 1-2G to back up. But if I run dump with the default settings, only a small amount of data is written before dump requests a new volume. So my question is: What are the right settings for the dump parameters -B (records), -b (blocksize), -d (density), and/or -s (feet) for this configuration? (Also, am I correct in assuming that this has nothing to do with the drive capacity and everything to do with the tape capacity?) Thanks in advance for your assistance. Matthew Saltzman Clemson University Math Sciences [EMAIL PROTECTED] http://www.math.clemson.edu/~mjs -- To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject.
