Specification Option - Copy on Close

Hi,

If the filter driver detects it as an open file, everything will be reserved.

However, this function is not usually used.

So what you mean is that if I'm running an incremental synch on 10,000 files and one of them is opened, Replistor won't process any of the 10,000 files until that file is closed?  Also, why is it that the function is usually not used?

Hi,

For example, the file of opened Oracle can synchronize.

Therefore, please sync by default if a problem does not occur.

Copy on Close perrofms a delayed sync of the open files.  Assuming this is not a UNC path type Source or Target, RS will wait until the file is closed on the Source and then it sends the entire file, not just the changed bytes of a file.  This can be dangerous if you nave some big files that are opened and closed during the day.  Each time it is closed the entire file must be sent to the Target.  That can use up the network in a hurry.  If the Copy on Close is not checked then Mirroring will only send the changed bytes after the spec is in-sync.  Under most circumstanced RS can replicate changes to open files.

The exception is when the Source node is sync'ing a NAS UNC path.  In that casem Mirroring usually does not work at all and scheduled Syncs are the best alternative.

Hi,

Only the file of the base is copied when opened to the memory.

Afterward, only the change part of the committing is copied if committed.

Moreover, it depends on the method of preserving the application.

There is a description in FAQ of the manager guide in detail.

Admin's Guide

------------------------------------------------------------------

If a user opens a Word file, makes a minor change to a
document and saves it, does RepliStor only send the changes
to the target? Is it inefficient to send the entire file to the target if
only a tiny portion is changed?
That depends. It is important to note that RepliStor is a slave to the
application. If the application writes 27 bytes, then RepliStor replays
that write of 27 bytes on the target. SQL Server or Outlook only
changes portions of the entire file. They never rewrite the entire file.
In that case, RepliStor does the same thing on the target.
Word and Excel tend to rewrite the file during the save. If RepliStor is
replicating it, the entire file is also rewritten on the target. In general,
Word completely rewrites the file. This is a function of Word, not
RepliStor. RepliStor only replays whatever the application has done.

------------------------------------------------------------------

Therefore, Oracle is not corrupted.

OK, thanks!  So basically checking the "Copy on Close "option will replicate the entire file once it is closed and can affect network performance if it's a big file.  Unchecking the option will still replicate the changed file even if it is open?  If it replicates just the partial, won't that corrupt the file?  For example if it is a big Oracle datafile we're updating and it only replicates a partial/change of that, won't that corrupt the Oracle datafile?  

Hi,

Synchronization starts at once only in the base part preserved on NTFS.

The change part will be kept in the kernel cache when committed while the base file is forwarding it.

And, when all the base files are copied, the change part is copied.

Hm, interesting.  Thanks for the information!!

OK, what we have discussed are files that already exist in the source.  What if I'm copying a NEW Oracle datafile TO the source, does Replistor wait until the file is finished copying to the source before replicating it over to the target?  Or, it starts replicating immediately even if the file isn't done copying?