I think what they mean by that is the following: The Out of Memory handler will kill processes to free up RAM and swap. However tmpfs' memory use is not caused by a (killable) process, so the OOM handler can't free it up. Anyway when the OOM handler kicks in you have a serious problem anyway, tmpfs or not ;-) On Wed, 2009-11-04 at 16:47 -0500, Brian Mathis wrote: > Looks good. I appreciate the discussion on the priority of the RAM > space used and issues to think about as far as swap space size and > when it starts using disk. > > One thing that concerns me in the tmpfs.txt file is this statement: > If you oversize your tmpfs instances the machine will deadlock > since the OOM handler will not be able to free that memory. > I assume that means you shouldn't allocate more to tmpfs than you have > physical memory, but I've also seen other sites suggesting to use > size=100% (vmware server tuning). So far I think 100% would be fine, > just not 110%. I'm not sure if you have any further insight into > that. > > Anyway, thanks for taking the time to address my comments. > > > On Wed, Nov 4, 2009 at 4:19 PM, Jasper Siepkes <jasper at siepkes.nl> wrote: > > Hi, > > > > First of all sorry for the long delay and thanks for the constructive > > feedback. > > > > I've made some additions to the Wiki article > > ( http://wiki.centos.org/TipsAndTricks/TmpOnTmpfs ): > > > > -Added the 'Practical details' section to explain how tmpfs, swap and > > memory relate. > > -Added a 'Pitfalls' section to warn people of an (IMHO) somewhat > > misguided piece of advice in the official documentation and maybe some > > other pitfalls when I think of them. > > > > About ramdisks; I will add something later about how tmpfs relates to > > other ramdisk implementations like cramfs and squashfs. But I haven't > > done much with the former two so I will need to research those a bit > > before I can write something down. > > > > I'm not the best writer on this continent (Shakespeare beat me by half a > > point, but I suspect foul play ;-) but I think I've made some steps in > > the right direction with the article. Please let me know what you think > > and where I should make some additional improvements. > > > > Regards, > > > > Jasper > > > > On Tue, 2009-10-20 at 14:38 -0400, Brian Mathis wrote: > >> On Tue, Oct 20, 2009 at 1:46 PM, Jasper Siepkes <jasper at siepkes.nl> wrote: > >> > Hi, > >> > > >> > I've made a first attempt at writing the tmpfs CentOS Tips and tricks item > >> > and I'm looking for some feedback. Does it need more (or less) background > >> > info ? Or more (or less) substance perhaps ? > >> > > >> > Regards, > >> > Jasper > >> > > >> > >> I'd like to see more info on things like: > >> - What is the relationship with swap? > >> - How/when does swap get used instead of RAM? > >> - How do I determine the size of RAM to use? > >> - What impact does using 100% of RAM have on the active memory in the system? > >> - What happens if all system RAM is full, and tmpfs is also full? > >> > >> I think your doc is a good start, but as of now it's got the same info > >> as all the other tmpfs docs out there, and they don't go into much > >> detail about the real impact on a system when using tmpfs. > >> > >> Tmpfs is billed as a more sophisticated ramdisk, so docs addressing it > >> should go into the details of what makes it better. A simple ramdisk > >> just allocates a chunk of RAM, so why is tmpfs better? > _______________________________________________ > CentOS-docs mailing list > CentOS-docs at centos.org > http://lists.centos.org/mailman/listinfo/centos-docs