On Fri, Mar 03, 2006 at 05:48:05PM -0600, Les Mikesell wrote: > > Fundamentally, I think that the hard link approach is a very cool hack, > > but i am hitting limits of it already, and my personal opinion is that a > > different approach (probably a RDBMS) is called for to index the backend. > > (night is day, black is white, filesystems are databases). > > As long as the disk head has to move for each operation, I don't > see how this is going to make a big difference.
that's just the thing, get rid of the hard links and the disk head does not, in fact, have to move so far for each operation. a hard link has to create a directory entry and update the inode it points to. these are generally non-local to one another but have to be on the same disk (or logical volume, but with an LVM scenario there is no way for the filesystem to know which real disk it is writing to so it's strictly hit or miss). an RDBMS could easily live on a different disk, and even if it lived on the same disk, it would not necessarily have to seek all the time - it would just have to update the database, since the inode would not have to be updated. It *is* true that updating a database can involve seeks, but this problem is understood by database developers and they optimize for it, eg, with logging. on a related note, one way that database installations are optimized for performance is by putting different things on different disks, to avoid the seek penalty. I recall that in the case of oracle, you can, in extreme cases, put something like 23 different things on 23 different disks. In the case of backuppc, i think the database part would be a tiny amount of data, and could easily live within a small region of the disk, so performance would likely be acceptable anyway. The actual file data could easily continue to live in the same pool/cpool directory structure. danno -- dan pritts - systems administrator - internet2 734/352-4953 office 734/834-7224 mobile ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ BackupPC-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/backuppc-users http://backuppc.sourceforge.net/
