On Friday, 16 December, 2011 18:54:46 you wrote: > Am Freitag, 16. Dezember 2011 schrieb Martin Steigerwald: > > Its not critical for me to fix these issues (soon), but I am curious > > whether its possible to get the filesystem speedier by some > > maintenance. > > Maybe after it is clear why it is so slow in the first place ;). I had the same experience. apt-get upgrade was a frustrating experience! IIRC the copy-on-write file-system in order to have good performance have to merge the write requests most as possible. Instead apt-get makes a lot of sync calls which don't allow btrfs to merge the write requests. This explains why btrfs is slow in this case. I found a solution, but requires a bit of setup. The idea is to avoid do perform sync during the package installation. In order to avoid data loss in case of failure, I create a snapshot before the upgrading. If something goes wrong (i.e. a power failure) I rebooot the system from the snapshot. If the installation finish without problem, I flush all the data to the disk and remove the snapshot. For the detail, see a my old post titled "[RFC] aptitude & BTRFS slow" (2011-10-19) BR G.Baroncelli -- gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreijack@xxxxxxxxx> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
