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CPU Usage during Duplicate


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The Duplicate process takes a relatively long time to clone my 40G powerbook hard drive (>2 hours, ~320,000 files) even when only a small subset of files are updated (using "replace corresponding"). One reason is that the "Closing" step takes almost half the time (which I understand is related to updating permissions). I did some investigating and found some interesting phenomenon related to CPU usage during this step (using "top"):

 

--"Finder" uses 10-25% of CPU, even though it is doing nothing. just a single window open.

--"WindowServer" uses 10-15% of CPU, presumably to draw the status bar and filenames in the script progress window.

--The Retrospect processes "LaunchCFMA" and "ATSServer" take up the remaining free CPU time = 40-50%.

 

I was apparently (?) able to improve retrospect performance (it appears this way to me, but I have not timed it yet to verify/prove) by giving more CPU time to LaunchCFMA through the following actions:

 

1. By quitting the Finder, 10-25% more CPU time is given to LaunchCFMA.

2. By "fast user switching" to the login window, WindowServer drops to 5%, giving ~10% more to LaunchCFMA.

3. Together, #1 and #2 can allow LaunchCFMA to use 80-90% of CPU time, when before it only used 40-50%. That's a big difference!!

 

Finally, and just as important, I notice that placing the "script progress window" in the background (when logged in) allows the "Closing" and "Verification" steps to apparently proceed much faster. this is suggested by a much faster (10-50X !!) screen redraw time (although maybe not all filenames are drawn when in the foreground??). I did not test previous steps in this way. ***It does not make sense to me that Retrospect would perform better when in the background*** (anyone have ideas about this?)

 

Summary: to combine all of the above info I would try:

 

1. Launch Retrospect and start a long "Duplicate" script.

2. Quit the Finder (can use Tinkertool for example to add quit menu to Finder)

3. Place a small application (e.g. TextEdit) in the foreground

4. Switch to the LoginWindow

 

maybe someone else can help me time these changes to see if they really make a difference? By the way, I monitor system processes and CPU time by ssh'ing in from another box and launching "top" remotely. I really wish there was a way to get Retrospect status information from the command line interface.

 

My system setup:

-client-server operation over 100BaseT ethernet

-server running Retrospect 6 on Panther 10.3.2 (upgraded Beige g3 -> g4/500, 512MB RAM)

-backup to extermal FW drive

-client (source) powerbook g4/800, 512 MB

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I have some good news for the forum readers. Our next free updated to Retrospect 6.0 (not the RDU update) will include a major performance increase for duplicates. In some cases duplicates will be 600% faster (during closing for permissions). I don't yet have a release date. mango.gif

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