On Thu, Oct 6, 2011 at 5:42 PM, Holger Parplies <wb...@parplies.de> wrote: > >> [...] >> With compressible data you increase both capacity and reliability by >> compressing before storage. There's no magical difference between the >> reliability of 'cat' vs 'zcat'. Either one could fail. > > the problem, I believe, is not 'cat' or 'zcat' failing, it's a *media* error, > as you pointed out, rendering a complete compressed file unusable instead of > only the erraneous bytes/sectors. Yes, there are compression algorithms that > are able to recover after an error, but I don't think BackupPC uses any of > these. > > Sure, the common case might be losing a complete disk rather than having a few > bytes altered, but in that case, you can either recover from the remaining > disks (presuming you have some form of redundancy), or you lose your complete > pool, whether or not compressed.
I like RAID1 where you can recover from any singe surviving disk. > While you might reduce the chances of failure with compression, you increase > the impact of failure. Maybe, maybe not. You might find something usable if you scrape some plain text or maybe even part of a tar file off a disk past a media error which is pretty hard to do anyway, but most other file types won't have much chance of working. -- Les Mikesell lesmikes...@gmail.com ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/