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View Full Version : Time Machine running 5X faster than SuperDuper


kennbrodhagen
07-19-2009, 10:23 AM
I recently purchased a Buffalo LinkStation NAS for backups and performed a Time Machine backup then a backup using SuperDuper.

The Time Machine backup completed in about 10-12 hours. The SuperDuper backup is now on hour 45 and is reporting about 85% complete.

Can anyone suggest why the SuperDuper backup is running so much slower than the Time Machine?

Here are some of my system statistics:
Mac OSX 10.5.7
Backing up 300 GB of used space on a 1 TB HDD
NAS is connected over gigabit ethernet

dnanian
07-19-2009, 11:51 AM
It's not typical that TM would be faster, but perhaps your LinkStation NAS (which is generally pretty slow) doesn't handle large files (the image) well? Time Machine uses "sparse bundles", which manage a large number of small file "bands" in a package, rather than a "sparse image", which uses a single large file...

kennbrodhagen
07-19-2009, 04:59 PM
I notice that after more than 50 hours now all of the files are still not "evaluated". Is it possible that it's the evaluation that's slowing it down and not the raw copy speed?

dnanian
07-19-2009, 06:35 PM
No, evaluation and copying are the same - it's a single pass copy.

kennbrodhagen
07-19-2009, 06:43 PM
The entire backup has now finished and reports an overall transfer rate of 1.66 MB/s.
I did a test with an 11.45 GB file and copied it to the NAS through Finder and got an overall speed of 6.5 MB/s. I can also hear the NAS drives working a lot more when I do a finder copy than when SD is running.

I checked the log and it doesn't appear to have any errors or warnings. It seems to log during the inital start of the backup and at the end when it closes out but not during file copy process itself.

Is there a way to set the logging to a debug level?

Is it possible that SD moves the file pointer around in the sparse image file a lot as it copies each file, like to update an index or something?

dnanian
07-19-2009, 06:46 PM
How the "file pointer" moves is entirely up to the system, as you might expect. We copy the entire file with a single low-level call, and then supplement the metadata as appropriate (which can take a few). Subsequent Smart Updates will be faster...