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#41
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In article ,
Arthur Begun wrote: I call it what it is. Backup Exec and other programs give you a choice between APPEND or OVERWRITE. It was an APPEND. If you don't like it, complain to them. If Backup Exec are rewriting the header they are not doing an append operation, they are combining an append operation with an overwrite operation, and lying to you about it. -- I've seen things you people can't imagine. Chimneysweeps on fire over the roofs of London. I've watched kite-strings glitter in the sun at Hyde Park Gate. All these things will be lost in time, like chalk-paintings in the rain. `-_-' Time for your nap. | Peter da Silva | Har du kramat din varg, idag? 'U` |
#42
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In article ,
Arthur Begun wrote: As far as Backup Exec causing the problem, I doubt it. Since it recognized that an error occurred and displayed an error message, I doubt it was writing anything further to the tape. It wouldn't have to. It was writing the header. If a failure occurred at that point, then you HAVE TO assume that any part of the header it was rewriting was in an unknown state: valid old, valid new, or invalid. It is incomprehensible to me that anyone would write archiving software that rewrote already-archived data or metadata without a way of recovering from any failure to safely update a copy of the data or metadata it was rewriting. If Backup Exec doesn't have a recovery mechanism that allows it to skip damaged sections of tape where that is physically possible and recover the remaining save sets from chained metadata then that is Backup Exec's problem. The backup software I use, AMANDA, never rewrites any data, and precedes each backup set with a descriptive file that not only describes what the following file will contain, but provides a plain text description that lets you know how to restore that backup set so you can recover the tape without even having the AMANDA software online. That is what I consider a "good" standard of care in designing archival and backup software. If your description of what Backup Exec does is accurate (which I must admit is increasingly doubtful) then it it isn't even doing a "minimally acceptable" job. -- I've seen things you people can't imagine. Chimneysweeps on fire over the roofs of London. I've watched kite-strings glitter in the sun at Hyde Park Gate. All these things will be lost in time, like chalk-paintings in the rain. `-_-' Time for your nap. | Peter da Silva | Har du kramat din varg, idag? 'U` |
#43
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#44
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#45
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The same thing would happen if you did this on a $100 used DDS drive or
on a $40000 Storagetek 9840 (or whatever they cost now). US$30k for a decent sized library.... http://cgi.ebay.com/ws/eBayISAPI.dll...ategory=37 56 |
#46
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"Rob Turk" wrote in message .nl...
"Arthur Begun" wrote in message om... I spent a good part of last night reading thru hundred's of newsgroup posts at Veritas Backup Exec website. They have a fine newsgroup, appears to be completely open and uncensored, with help provided by Veritas and users. And it has great searching abilities. Searched on "header" and anything else I could think of that might be related to what happened. The newsgroup goes back about 5 years with thousands of posts of problems with various versions of Backup Exec. NOT A SINGLE REPORT OF A TAPE READING ZERO OR BLANK AFTER AN APPENDED BACKUP. NOT ONE!!! NOT A SINGLE ONE. CLEAR ENUF TO YOU GUYS????? Interesting... My 3 minutes on the Veritas web site brought me to the following hit: http://seer.support.veritas.com/docs/233735.htm So although you found no hits of anyone discussing a similar issue, Veritas has discovered such a flaw in their software before. Please note the line that says "NOTE: These errors are not completely indicative of the problem and could be displayed during other operations" Also read: "In rare situations, it is possible for a COM communication link to be broken prematurely." Your system hung and/or you cut power before the backup was complete. I think we can all agree that at that point COM communications was gone too. Rob Obviously I found that link in my hours of searching and considered it. I believe it is evidence that Backup Exec did not do the damage. In the case of software damage to the header, the result was (according to the document) that the tape became "Unrecognized Media" the next time it was loaded into Backup Exec. My media remained recognized, with name undamaged, but it was blank. |
#47
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#48
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#49
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#50
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"Arthur Begun" wrote in message
om... "Rob Turk" wrote in message .nl... Interesting... My 3 minutes on the Veritas web site brought me to the following hit: http://seer.support.veritas.com/docs/233735.htm So although you found no hits of anyone discussing a similar issue, Veritas has discovered such a flaw in their software before. Please note the line that says "NOTE: These errors are not completely indicative of the problem and could be displayed during other operations" Also read: "In rare situations, it is possible for a COM communication link to be broken prematurely." Your system hung and/or you cut power before the backup was complete. I think we can all agree that at that point COM communications was gone too. Rob Obviously I found that link in my hours of searching and considered it. I believe it is evidence that Backup Exec did not do the damage. In the case of software damage to the header, the result was (according to the document) that the tape became "Unrecognized Media" the next time it was loaded into Backup Exec. My media remained recognized, with name undamaged, but it was blank. This very statement invalidates your entire story. The name of your media is in the very first data blocks of rolling drums the HEADER. If BackupExec is able to identify the tape by name, then your tape is NOT blank. Rob |
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