Hi, Jeffrey J. Kosowsky wrote on 2011-10-06 22:09:52 -0400 [Re: [BackupPC-users] Bad md5sums due to zero size (uncompressed) cpool files - WEIRD BUG]: > Holger Parplies wrote at about 02:45:56 +0200 on Friday, October 7, 2011: > > Jeffrey J. Kosowsky wrote on 2011-10-06 19:28:38 -0400 [Re: > [BackupPC-users] Bad md5sums due to zero size (uncompressed)?cpool files - > WEIRD BUG]: > > > > > > Actually this could be made even faster since there seem to be 2 > > > cases: > > > 1. Files of length 8 bytes with first byte = 78 [no rsync checksums] > > > 2. Files of length 57 bytes with first byte = d7 [rsync checksums] > > > > > > So, all you need to do is to stat the size and then test the > > > first-byte > > [...] > > An additionally running 'find' does report some 57-byte files, but they > > don't seem to decompress to "". > > Do those 57 byte files have rsync checksums or are they just > compressed files that happen to be 57 bytes long?
well, I implemented your suggestion quoted above to determine whether they would decompress empty, so they are just compressed files that happen to be 57 bytes long. Actually, I included a debug option to output 57 byte files with a first byte \x78, and they seem to show up there (I didn't check if all do, I was only interested in checking my implementation). My point was that 'find cpool \( -size 8c -o -size 57c \)' does show quite a number of hits - so many that it's hard to see whether there are any 8-byte files in between - and the 57-byte ones are pointless, because you'd have to individually determine whether they are just compressed files that happen to be 57 bytes long or empty compressed files with checksums. I simply hadn't expected that. 'find cpool -size 8c' should still be useful as a lightweight check for your first case. > Given that the rsync checksums have both block and file checksums, > it's hard to believe that a 57 byte file including rsync checksums > would have much if any data. I thought you were positive that it can't. Actually, your reasoning seems to say that it can't, but what about an 8-byte file without checksums? There's not much point in looking for 8-byte files with a \x78 if it's uncertain that they're really empty - at least we'd need to decompress to check. Regards, Holger ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ BackupPC-users mailing list [email protected] List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
