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Old 11-10-2009, 07:44 PM   #556
mejohnsn
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Quote:
Originally Posted by AwesomeMachine View Post
Ghost also has huge license fees that DD lacks. In a corporate environment, dd can save tens of thousands of dollars per year over Ghost.
You are missing the point. Alone, 'dd' can do no such thing. It has to be combined, as I think you are already actually quite well aware, with other tools, such as 'tar'.

Combined with other tools, yes, it can save tens of thousand of dollars per year over Ghost. But so can 'cpio', which is about as old a tool. 'cpio' makes more efficient use of the backup media space, too.

So why does anyone persist in using Ghost? I don't think slick marketing can explain this completely. It must be because Ghost is easier to use and easier to justify to the purchasing department.

After all: if the backup software screws up, with Ghost, you have at least a ghost of a chance (pun intended) of legal redress. But with 'dd' and 'cpio', you have none. This line of reasoning, weak though it is (license agreements usually try to disclaim any warranty), is nevertheless powerfully persuasive to the purchasing department.

Nevertheless, I am sure a lot of us would be very pleased if wider knowledge of how to use free, already included Linux tools such as 'dd', 'tar' 'gzip' and 'cpio' would create enough downward pressure on the license fees for Ghost, so that we would no longer be talking about saving tens of thousands.

But if we want this knowledge to spread, we MUST avoid misleading statements like "'dd' is equivalent to Ghost". It simply is not so.
 
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Old 11-17-2009, 12:29 AM   #557
AwesomeMachine
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You miss the point ...

Quote:
Originally Posted by mejohnsn View Post
You are missing the point. Alone, 'dd' can do no such thing. It has to be combined, as I think you are already actually quite well aware, with other tools, such as 'tar'.

Combined with other tools, yes, it can save tens of thousand of dollars per year over Ghost. But so can 'cpio', which is about as old a tool. 'cpio' makes more efficient use of the backup media space, too.
This isn't a contest. If you read through the entire OP, no one is commanding anyone else that they have to do what's in the post. If you don't want to, don't. In my understanding, having used Ghost, dd and Ghost are about the same.

Quote:
Originally Posted by mejohnsn View Post
So why does anyone persist in using Ghost? I don't think slick marketing can explain this completely. It must be because Ghost is easier to use and easier to justify to the purchasing department.

After all: if the backup software screws up, with Ghost, you have at least a ghost of a chance (pun intended) of legal redress. But with 'dd' and 'cpio', you have none. This line of reasoning, weak though it is (license agreements usually try to disclaim any warranty), is nevertheless powerfully persuasive to the purchasing department.
I think the main draw to Ghost is Windows.

Quote:
Originally Posted by mejohnsn View Post
Nevertheless, I am sure a lot of us would be very pleased if wider knowledge of how to use free, already included Linux tools such as 'dd', 'tar' 'gzip' and 'cpio' would create enough downward pressure on the license fees for Ghost, so that we would no longer be talking about saving tens of thousands.

But if we want this knowledge to spread, we MUST avoid misleading statements like "'dd' is equivalent to Ghost". It simply is not so.
To you it isn't true, because you're caught up in details. At the end of the day, when all the hard drive images are done, it doesn't matter how the imaging was accomplished. It matters that it got done right. And, the monetary compensation possible for any software failure is limited to the purchase price of the software, unless otherwise specified.

If you have anything constructive to add to the thread, please do. If not, don't

-Awesome

Last edited by AwesomeMachine; 11-23-2009 at 05:10 AM. Reason: Tinks Post
 
Old 11-17-2009, 12:54 AM   #558
prashant.saraf
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Gr8 and very helpful post. Thanks a ton!!!
 
Old 11-17-2009, 02:03 AM   #559
mejohnsn
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Quote:
Originally Posted by AwesomeMachine View Post
This isn't a contest. If you read through the entire OP, no one is commanding anyone else that they have to do what's in the post. If you don't want to, don't. In my understanding, having used Ghost, dd and Ghost are about the same. Do you work for Symantec?
You are still missing the point. By continuing to miss the obvious, you are the one pretending it is a contest -- a contest in obstinacy.

I read through the entire OP, painful as it was. That it is not 'commanding' is quite beside the point. What it is claiming is simply wrong. 'dd' and Ghost are NOT "about the same". 'dd' does not do incremental backups, Ghost does.

This in addition to the differences I already pointed out, which are by no means minor.

You claim to have used Ghost, how could you fail to notice this difference? Do you really think the ability to do incremental backups is so minor? Or are you blinded by your Linux fanboy attitude, so that you cannot see how different a tool without incremental backup support is from Ghost?
 
Old 11-17-2009, 03:17 AM   #560
AwesomeMachine
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Post The Lone Authority ...

Quote:
Originally Posted by mejohnsn View Post
You are still missing the point. By continuing to miss the obvious, you are the one pretending it is a contest -- a contest in obstinacy.

I read through the entire OP, painful as it was. That it is not 'commanding' is quite beside the point. What it is claiming is simply wrong. 'dd' and Ghost are NOT "about the same". 'dd' does not do incremental backups, Ghost does.
Mejo,

Ghost and dd are not exactly the same. Ghost doesn't even run under Linux. If a person wants to do incremental back-ups, they don't need a drive imaging program. I could write a program that burns CDs and calculates rf antenna output power. Then I could say, "No other CD burning program can do what this one can do Because this one also calculates total radiated rf output power".

Making a drive image program do incremental file back-ups just places two completely different programs on the same menu. Either one wants to image a drive, which has certain advantages over file based back-ups; or he wants to back-up files. Those two things are discrete, and don't necessarily belong together under the same software title.

Perhaps Ghost can duplicate a drive image, and then do incremental backups against the drive image. That would be novel. But what people like about Ghost is the drive imaging capability. There are thousands of file back-up programs. There are only a few real drive imagining programs.

And, I think what Symantec did was buy Powerquest Software and Norton Software, and then combined Powerquest Drive Image with Norton Ghost, producing Symantec Norton Ghost. Norton had a bigger name at that time. So the Powerquest brand name got dumped in favour of the Norton brand name.
Ghost does perform functions that would be difficult to do with dd. But dd is an authentic *nix tool. Ghost is proprietary closed source software. For all you know, Ghost might be opening a TCP/IP connection, and as it images the data, it sends a copy to Symantec Corporation. End users never really know what closed source software is doing.

Oss source code has been peer reviewed, by the foremost computer security experts in the world.

Quote:
Originally Posted by mejohnsn View Post
This in addition to the differences I already pointed out, which are by no means minor.

You claim to have used Ghost, how could you fail to notice this difference? Do you really think the ability to do incremental backups is so minor? Or are you blinded by your Linux fanboy attitude, so that you cannot see how different a tool without incremental backup support is from Ghost?
I use Linux because of its flexibility, stability and power. Linux is a flexible, power user os. I can tell you're a little resentful about something. Just try to do something constructive. Symantec Corporation doesn't need your help selling Ghost. Or maybe they do. If you work for Symantec, and you would like corrections made to the OP; produce proof of your credentials in a PM, state your case, and I'll take a look at it.

I'm not trying to cut into corporate profits. Open source software has its own costs; like it is difficult to learn. But that's why I made the OP.
 
Old 11-17-2009, 08:40 AM   #561
pixellany
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@Awesome* and @mejohn*;

I think that's enough.....I really doubt if either of you is going to convince the other. In a couple of places, it's getting a bit too personal.

@mejohn*;
This thread is solely about how to use the dd command. I sense that you have some issues which go beyond this. It may be better to find a more appropriate thread or start a new one.
 
Old 11-17-2009, 01:10 PM   #562
Tinkster
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Guys, quite the pissing contest, edit your posts and take the personal
attacks out. Or I will, and give you both a break of a few days.



Cheers,
Tink
 
Old 11-17-2009, 07:25 PM   #563
mejohnsn
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Quote:
Originally Posted by pixellany View Post
@Awesome* and @mejohn*;

I think that's enough.....I really doubt if either of you is going to convince the other. In a couple of places, it's getting a bit too personal.

@mejohn*;
This thread is solely about how to use the dd command. I sense that you have some issues which go beyond this. It may be better to find a more appropriate thread or start a new one.
No, that is not all it is about. It is about how to use the 'dd' command for several purposes, conspicuously for backups. It is not even about all the uses of the 'dd' command (though many good examples are at least mentioned), nor about all the different ways about backups.

And don't get me wrong: I do recognize there is valuable material in the article. But I will say it again: it detracts from the valuable material to taint it with misinformation, such as "'dd' is equivalent to Ghost".

Again: to be equivalent to Ghost, 'dd' would have to be standalone, and would have to support incremental backups. The fact 'Awesome' point out, that historically full and incremental backups were provided by two distinct programs, now joined at the waist in Ghost, is interesting. But it is interesting only from a historical perspective. It does not change the basic fact: Ghost does what 'dd' alone cannot do. So no equivalence.

Also, the UI would have to be designed such that all the many good warnings and cautions in the article (about commands where a small typo can cause massive data destruction) are not necessary. Again, no equivalence.

If after reading the article, whether you read all these posts or not, you decide 'dd' is the tool for you and not Ghost, fine. More power to you. Just don't fool yourself into thinking that the two are equivalent. You will only make headaches for yourself if you do.

Finally, just to confuse anyone who still suspects me of being a Symantec shill: I have not ever used Ghost and I do not plan to. All the assertions about it in these posts rely on what I found using Google searches.
 
Old 11-17-2009, 07:27 PM   #564
mejohnsn
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Quote:
Originally Posted by pixellany View Post
@Awesome* and @mejohn*;

I think that's enough.....I really doubt if either of you is going to convince the other. In a couple of places, it's getting a bit too personal.

@mejohn*;
This thread is solely about how to use the dd command. I sense that you have some issues which go beyond this. It may be better to find a more appropriate thread or start a new one.
How you sense 'issues' in the plural, when there has been only one, is a mystery to me.

That one issue is: the article asserts an equivalence between 'dd' and Ghost, but they are by no means equivalent. Not even close.

Last edited by mejohnsn; 11-17-2009 at 07:33 PM. Reason: typo
 
Old 11-18-2009, 08:24 AM   #565
pixellany
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@mejohnsn;

You may be right, but let it go please.

Contact me or any moderator if you need to discuss further.

thank you
 
Old 11-20-2009, 12:56 PM   #566
blnl
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Question

Great post, plenty of information.

I was searching for an answer for my problem, but was not able to find it.
Maybe you could point me in the right direction?



I'm performing regular backup of my ext3 partition as follows:
Code:
dd if=/dev/hda3 conv=sync,noerror bs=64K | gzip -c > nc6000_linux_system.img.gz
Now is the time to restore my partition from an old image:
Code:
gunzip -c nc6000_linux_system.img.gz | dd of=/dev/hda3 conv=sync,noerror bs=64K
The dd operation failed with the following message:
Code:
dd: writing '/dev/hda3': No space left on device
3673+348340 records in
352012+0 records out
23069491200 bytes (23 GB) copied, 713.275 s, 32.3 MB/s
Why the image does not fit on the drive any more?
What am I doing wrong?
 
Old 11-22-2009, 05:42 PM   #567
blnl
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Thumbs up

In spite of the "No space left on device" message, the restore operation was successful and my system boots normaly.

I'm interested to hear the explanation, if any!
 
Old 11-23-2009, 05:27 AM   #568
AwesomeMachine
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Post Dd and the pipe (|)

Quote:
Originally Posted by blnl View Post
I'm performing regular backup of my ext3 partition as follows:
Code:
dd if=/dev/hda3 conv=sync,noerror bs=64K | gzip -c > nc6000_linux_system.img.gz
Now is the time to restore my partition from an old image:
Code:
gunzip -c nc6000_linux_system.img.gz | dd of=/dev/hda3 conv=sync,noerror bs=64K
The dd operation failed with the following message:
Code:
dd: writing '/dev/hda3': No space left on device
3673+348340 records in
352012+0 records out
23069491200 bytes (23 GB) copied, 713.275 s, 32.3 MB/s
Why the image does not fit on the drive any more?
What am I doing wrong?
In the command line to restore, dd is dependent on gunzip feeding it image data. Because of the sync parameter, dd pads the last block with zeroes to make it a full block. So dd keeps going after the image.gz file is written. No space left on device is not an error. Many uses of dd require the device to run out of space. It's not a problem. But the sync conversion is helpful for the method of backup you are using (gzip).

Last edited by AwesomeMachine; 11-23-2009 at 05:34 AM.
 
1 members found this post helpful.
Old 11-23-2009, 06:24 PM   #569
aus9
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AwesomeMachine

slight hijack....nothing personal.

I can see this post scoring a million views very shortly ....which is awesome.
 
Old 11-23-2009, 06:35 PM   #570
exvor
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I recently discovered partimage for backing up partitions. If its a whole drive then I would use DD. Partimage is a nice tool with a ncurses like gui interface, it does however get some getting used to since some things are not quite explained right.
 
  


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