On Mon, 29.07.13 13:48, Eric Sandeen (sandeen@xxxxxxxxxx) wrote: > > Well, I am pretty sure the burden must be on the file systems to report > > a useful estimate free blocks value in statfs()/statvfs(). Exporting that > > problem to userspace and expecting userspace to work around this is just > > wrong. In fact, this would be quite an API breakage if applications > > cannot rely that the value returned is at least a rough estimate on how > > much data can be stored on disk. > > > > journald will scale how much disk usage it will use of /var/log/journal > > based on the file system size and free level. It will also module the > > per-service rate limit levels based on the amount of free disk space. If > > you break the API of statfs()/statvfs(), then you will end up break this > > and all programs like it. > > Any program needs to be prepared for ENOSPC; as Ric mentioned elsewhere, > until you successfully write to it, it's not yours! :) (Ok, thinp > running out of space won't generate ENOSPC today, either, but you see > my general point...) Oh, we don't assume it's all ours. We recheck regularly, immediately before appending to the journal files, of course assuming that we are not the only writers. > And how much space are we really talking about here? If you're running > thin-provisioning on thin margins, especially w/o some way to automatically > hot-add storage, you're probably doing it wrong. journald will by default allow the journal files to grow to 10% of the filesystem size of /var/log/journal, but will make sure that 15% is always kept free. This really is just about finding some useful parameters for sizing things that are likely to just work. It's not at all about making any algorithms depending on that, a way to avoid ENOSPC handling or anything like that. It's just about finding some sensible default metircs. Lennart -- Lennart Poettering - Red Hat, Inc. -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
