The return of SEEK_HOLE

Posted May 9, 2011 1:11 UTC (Mon) by foom (subscriber, #14868)
In reply to: The return of SEEK_HOLE by guest
Parent article: The return of SEEK_HOLE

Well, there's at least one use for them: some machines I've used have had a terrabyte-long /var/log/lastlog file, due to uid -1 being inserted in it, or something like that. It would've been a shame if that actually took a terrabyte of disk space (although that's actually feasible now!). :)

Of course, on the problems side, this caused havoc with RPM, since under some conditions I don't really understand, it would try to read and checksum the entire file, every time you tried to install a package. But hey, just need to teach RPM about SEEK_HOLE, and it'll be all great!

The return of SEEK_HOLE

Posted May 11, 2011 21:34 UTC (Wed) by nix (subscriber, #2304) [Link]

Other major holey files include quotas, coredumps, and some sorts of disk image (including, the biggie, virtual machine disk images). Of course there are virtual machine disk image formats that do *not* require holes, but either they allocate a lot of space right off or they basically have to reimplement holes at a higher level...