On Tue, Dec 05, 2006 at 05:47:23PM -0600, Mike McCarty wrote: > Johannes Wiedersich wrote: > >Douglas Tutty wrote: > > > >>I'm going to be backing up to a portable ruggedized hard drive. > >>Currently, my backups end up in tar.bz2 format. > >> > >>It would be nice if there was some redundancy in the data stream to > >>handle blocks that go bad while the drive is in storage (e.g. archive). > >> > >>How is this handled on tape? Is it built-into the hardware > >>compression? > >> > >>Do I need to put a file system on a disk partition if I'm only saving > >>one archive file or can I just write the archive to the partition > >>directly (and read it back) as if it was a scsi tape? > >> > >>Is there an archive or compression format that includes the ability to > >>not only detect errors but to correct them? (e.g. store ECC data > >>elsewhere in the file) If there was, and I could write it directly to > >>the disk, then that would solve the blocks-failing-while-drive-stored > >>issue. > > > > > >Now, to something completely different.... > >If data integrity is your concern, than maybe a better solution than > >compression is to copy all your data with rsync or another backup tool > >that 'mirrors' your files instead of packing them all together in one > >large file. If something goes wrong with this large file you might loose > >the backup of all your files. If something goes wrong with the > > [snip] > > My understanding of the BZ2 format is that it compresses individual > blocks independently, and that the loss of a block will not compromize > the entire archive, only those files which are contained in a given > block.
Yes. But I don't want to loose any data at all. I've looked at par2. It looks interesting. For me, the question is how to implement it for archiving onto a drive since the ECC data are separate files rather than being included within one data stream. Separate files suggests that it be on a file system, and we're back to where we started since I haven't found a parfs. I suppose I could use par2 to create the ECC files, then feed the ECC files one at a time, followed by the main data file, followed by the ECC files again. I'll check out with my zip drive if I can write a tar file directly to disk without a fs (unless someone knows the answer). Doug. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
