On 12/13/13 at 02:18pm, Zbigniew Jędrzejewski-Szmek wrote: > On Fri, Dec 13, 2013 at 01:49:51PM +0800, WANG Chao wrote: > > On 12/13/13 at 06:42am, Zbigniew Jędrzejewski-Szmek wrote: > > > On Fri, Dec 13, 2013 at 01:33:17PM +0800, WANG Chao wrote: > > > > Hi, > > > > > > > > In kdump environment, memory resource is quite limited. I find that the > > > > runtime journal file (/run/log/journal/$id/system.journal) is 4 MB and I > > > > think that is too much for a initramfs context. > > > > > > > > After tuning both RuntimeMaxUse=1% or RuntimeMaxFileSiz=100K, I find > > > > system.journal is still 4 MB in size. So here comes my questions: > > > > > > > > 1. Did miss use of these two config options? Because regarding the > > > > journald.conf(5), it seems I was totally doing it right. > > > 4MB is the minimum. Those settings are ignored if you set anything > > > lower. > > > > Is there any particular reason? I think thresold for runtime journal > > size can lower much because in initramfs it's not supposed to have much > > logs. > First, there are some data strcutures which are allocated when the file > is created, and if the file was very small, relatively more space would > wasted. Second, repeated fields are not stored, just referenced, so things > become more efficient when the file is not too small. But neither is > fundamental reason, and with some tweaking the journal could be made > to work much smaller files.
I understand. These are really good points when logs are relatively large, ie. the journal is stored on a real disk. However when it's in initramfs context, journal is stored in tmpfs which is using the real memory resource as it's backend. 4 MB seems a little bit overkill especially when memory is quite limited case, like kdump. To be more specific, I think 512 KB or 1 MB is a fairly large enough nubmer when journal is stored to a volatile backend. Thanks WANG Chao _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel