I am having the same problem described in this post.
I am currently evaluating FBackup. I performed two backups: Mirror and Full Backup.
I am backup up an entire HD, about 50 GB, and backing up to an external USB HD.
The Mirror backup completed in 10 hours, and then the Testing phase completed within 2 hours. Very good. Here is the log:
Backup job "Mirror" at 12/12/2010 2:22:45 AM
Backup:
Total number of files added to backup: 146260
Total number of folders added to backup: 14629
Total size of files added to backup: 50,331,775.75 KB
Number of files excluded: 8
Number of folders excluded: 0
Files skipped: 8
Next scheduled backup:
Backup completed at 12/12/2010 1:14:23 PM with 0 error(s), 8 warning(s)
Test:
Starting test on "Full Backup" for all backup numbers at 12/12/2010 12:20:51 PM
Test finished at 12/12/2010 1:14:23 PM, 146260 file(s) and 14629 folder(s) tested, 0 error(s) and 0 warning(s) found
Now I am running a "Full Backup" which stores files in Zip64 format. The backup completed relatively quickly (7 hours), but now that it is performing the testing phase, it is taking an extremely long time (31 hours so far, to reach 12% complete).
Here are some excerpts from the current running log:
[12/12/2010 4:09:16 PM] Creating the list of files to backup
[...]
[12/12/2010 4:15:48 PM] Folders found to backup: 14,636
[12/12/2010 4:15:48 PM] Files found to backup: 146,372 (50,502,366.13 KB)
[12/12/2010 4:15:59 PM] Preparing shadow copy
[12/12/2010 4:16:22 PM] Shadow copy created.
[12/12/2010 4:16:23 PM] Archiving files to 1_C.zip
[...]
[12/12/2010 11:27:00 PM] Saving backup catalog "{CATALOG_NAME}.fkc"
[12/12/2010 11:28:37 PM] Starting test on "Zip Full Backup" for all backup numbers at 12/12/2010 11:28:37 PM
[12/12/2010 11:29:18 PM] Testing content of zip I:\BACKUPS\Zip Full Backup\1_C.zip
[12/12/2010 11:29:22 PM] AUTOEXEC.BAT OK
[12/12/2010 11:29:26 PM] boot.ini OK
[12/12/2010 11:29:29 PM] CONFIG.SYS OK
[12/12/2010 11:29:33 PM] IO.SYS OK
[12/12/2010 11:29:36 PM] MSDOS.SYS OK`
As you can see, when it starts testing files, it takes a few seconds for each file. This is in contrast to how long it took to archive the files:
[12/12/2010 4:17:01 PM] Added file C:\AUTOEXEC.BAT
[12/12/2010 4:17:01 PM] Added file C:\boot.ini
[12/12/2010 4:17:01 PM] Added file C:\CONFIG.SYS
[12/12/2010 4:17:01 PM] Added file C:\IO.SYS
[12/12/2010 4:17:01 PM] Added file C:\MSDOS.SYS
It took almost no time at all to store these files into the archive, but reading them back out of the archive seems to take some effort.
Reading from the end of the log (the test is still in progress), it appears that it is taking several seconds per file to access each one:
[12/13/2010 6:04:30 PM] Windows\ServicePackFiles\i386\sprb041b.dll OK
[12/13/2010 6:04:37 PM] Windows\ServicePackFiles\i386\sprb0424.dll OK
[12/13/2010 6:04:43 PM] Windows\ServicePackFiles\i386\sprc041b.dll OK
[12/13/2010 6:04:49 PM] Windows\ServicePackFiles\i386\sprc0424.dll OK
I suspect that FBackup may be using some sort of inefficient algorithm in processing the ZIP64 file. Perhaps it closes and reopens the file for every test, or must reread and reparse the ZIP catalog, or it needs to seek/read through the entire ZIP file to find the file and test it. It is not clear to me that it should really take this much time.
I have seen a comment posted here in this forum that "Some drives read much slower than they write," but that really is sort of nonsensical; there is no such drive. At any rate, there was no slow-down in testing the Mirror backup, so I am surprised at the slow performance of the ZIP64 backup.
Since I did not do anything special to set up my backup, I would be surprised if you cannot duplicate this same performance problem in your lab. It seems relatively easy.
At the rate this is going, if I assume 6 seconds to test each file, times 146,372 files backed up, I estimate the testing phase will take around 244 hours (10 days) to complete.
