"David Rees" writes: > On 5/11/06, Lee A. Connell <[EMAIL PROTECTED]> wrote: > > > > I noticed while monitoring backuppc that it doesn't seem to compress > > on the fly, is this true? I am backing up 40GB's worth of data on a > > server and as it is backing up I monitor the disk space usage on the > > mount point and by looking at that information it doesn't seem like > > compression is happening on the fly. > > > > Does compression happen after the backup completes? > > Whether or not compression is an option during the data transfer > depends on the transfer method. Currently, the only backup method > which supports compression over the network is ssh+rsync, and that > relies on ssh to do the compression. All others will send the data > over the network uncompressed. > > Backuppc gets the data in uncompressed form, so it will compress the > data at that point if compression is enabled.
The net effect is as you describe, but it works slightly differently. When comparing the incoming file with candidate pool files it actually uncompresses the pool file and compares that with the incoming data. That's because uncompressing is faster than compressing. If there is no match (or a failed match), then, yes, the file is compressed as it is written to disk. The uncompressed file is not written to disk. There is one case when a pool file is uncompressed to disk. With rsync, if file deltas on a large file are processed, the underlying file is first uncompressed to disk. This file is a temporary file that is removed when the file deltas are merged. Craig ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid0709&bid&3057&dat1642 _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/backuppc-users http://backuppc.sourceforge.net/
