Florian Festi wrote: > Eric Sandeen wrote: >> - rpm? (file installation and/or db files?) > > The rpmdb is a bunch of db4 files. In don't think I want to interfere with > the db4 engine... They're often badly fragmented, too :) But whether or not that matters much for rpm performance, I dunno. [root@host ~]# filefrag /var/lib/rpm/Packages /var/lib/rpm/Packages: 844 extents found, perfection would be 1 extent [root@host ~]# ls -lh /var/lib/rpm/Packages -rw-r--r-- 1 rpm rpm 52M Apr 27 15:40 /var/lib/rpm/Packages [root@host ~]# du -h /var/lib/rpm/Packages 52M /var/lib/rpm/Packages > I am not really sure whether preallocation offers that much benefit for file > installation. May be if there is a parallel process also writing to the disk > heavily - but such processes should probably have their own partition/disk. > Would preallocation make sense for tar? > > Let's ask the other way round: What are the costs of preallocation for - say > 2M files with 50GB overall content? > > Florian I wouldn't use it for every file; it may not even make sense for this application, I was just throwing things out :) A reasonable test might be to do a fresh install (maybe a mock chroot install?) and go look to see if things are fragmented afterwards, and if it's bad enough to warrant a change. Thinking more about it, it's probably not needed, most of these files are small and with delayed allocation, layout should be fine. I don't want to spur a new generation of perfect-allocation fetishists, but in places where poor allocation may impact performance (or adversely affect later allocations by badly fragmenting freespace) it's worth considering the tool. -Eric -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
