On Tue, Jan 29, 2013 at 7:04 AM, Travis.Schwenke
<travis.schwenke AT gmail DOT com> wrote:
>
> Using SMB, a full backup was taking about 3.5 hours and an incremental about
> 10 minutes on a particular client.
>
> When I switched to ssh/rsync (Cygwin on Win7), a full was about the same and
> so were incrementals! That was a pretty drastic increase in the time for an
> incremental to complete. But now I think the SMB based full and
> incrementals have dropped out of the pool and yesterday’s incremental was
> only 2 hours and todays was 20 minutes.
>
> Is this normal for rsync to operate this way?
It is complicated.... Rsync fulls will always do a full read of the
files on the target system for the block checksum comparison. For the
first 2 rsync fulls of any file, the server side will also
read/uncompress the file for the comparison. If you have checksum
caching enabled, after the 2nd full, the server will use the
previously computed checksums as long as they match except for a small
fraction of files. Incrementals will skip files where the timestamp,
length, and other attributes match - but those might appear to be
different in some way from the smb backups. In case of differences,
the contents of the file will be read for the block-checksum
comparison. Where there are differences in the files, rsync may be
slower than smb as it creates a full new copy by merging the old with
the differences. This uses less network bandwidth but has more disk
activity.
My advice is to make sure you have enabled checksum caching and not
worry about it too much unless the overall time is a problem for your
backup window. And you are probably better off keeping your current
backups down to 2 or so.
--
Les Mikesell
lesmikesell AT gmail DOT com
------------------------------------------------------------------------------
Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS,
MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current
with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft
MVPs and experts. ON SALE this month only -- learn more at:
http://p.sf.net/sfu/learnnow-d2d
_______________________________________________
BackupPC-users mailing list
BackupPC-users AT lists.sourceforge DOT net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/
|
