Hello, hopefully a simple question.
Let's say I wish to Mirror my music folder to a new, currently empty,
external backup drive. If I set FFS to Mirror the music folder with the
selected comparison method being File Content, will it compare the
contents of the new files with the originals, as each one is created on
the backup drive?
Or, when there is no pre-existing file of the same name in the
destination folder, will it just do a straight copy without doing the
bit-by-bit check?
Thank ls in advance for any help.
File content comparison question
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The FFS manual regarding Comparison Settings (https://freefilesync.org/manual.php?topic=comparison-settings) is very clear on this:
When using File Content as the comparison method (F6),
there can be either of four comparison results.
1) file exists on left side only
2) file exists on right side only
3) file exists on both sides and have equal content
4) file exists on both sides and have different content
Now, when you select a Synchronization (F8) variant other than Two Way, you will see the above four Categories and below those the associated Action for that Category.
You probably want to use the Mirror or Update variant, but you can define your own Custom Action for each Category.
When you check for above Category 1), both for Mirror and Update the default Action is to copy the item left to right. Obviously that will be done without further comparison, as there is nothing to compare with ...
When using File Content as the comparison method (F6),
there can be either of four comparison results.
1) file exists on left side only
2) file exists on right side only
3) file exists on both sides and have equal content
4) file exists on both sides and have different content
Now, when you select a Synchronization (F8) variant other than Two Way, you will see the above four Categories and below those the associated Action for that Category.
You probably want to use the Mirror or Update variant, but you can define your own Custom Action for each Category.
When you check for above Category 1), both for Mirror and Update the default Action is to copy the item left to right. Obviously that will be done without further comparison, as there is nothing to compare with ...
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- Joined: 24 Apr 2013
Hello, this is a response to the thread I initiated "File content
comparison question" at:
viewtopic.php?t=607
(sorry, I cannot see any way to reply there)
If I have understood correctly, when a file exists on the left only, it
is copied to the right without then being compared /after the fact/ for
file content equality.
In other words, if I mirror or update files I will then have to do
another FC comparison after the mirror is completed, to check that both
sides are content identical.
So if I could make a feature request, it would be for some sort of
tickable "post copy" option for file content comparison of any new files
created on the right, when using the FC method.
That way when the mirror/update is all done, and FFS is showing all
files as equal between the left and right, we can be certain that ALL
files have now been verified as equal, not just the ones that where
already on both left and right before you first started.
Just an idea, I hope its OK. Thanks again.
comparison question" at:
viewtopic.php?t=607
(sorry, I cannot see any way to reply there)
If I have understood correctly, when a file exists on the left only, it
is copied to the right without then being compared /after the fact/ for
file content equality.
In other words, if I mirror or update files I will then have to do
another FC comparison after the mirror is completed, to check that both
sides are content identical.
So if I could make a feature request, it would be for some sort of
tickable "post copy" option for file content comparison of any new files
created on the right, when using the FC method.
That way when the mirror/update is all done, and FFS is showing all
files as equal between the left and right, we can be certain that ALL
files have now been verified as equal, not just the ones that where
already on both left and right before you first started.
Just an idea, I hope its OK. Thanks again.
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As pointed out earlier in other posts in this forum, a "verify" function after a copy action is not reliable, as in many cases the file that has just been copied might be read from cache rather than from disk.
If the file still (co)resides in cache, there apparently is no way to force a read from disk.
If the file still (co)resides in cache, there apparently is no way to force a read from disk.
