On 06/23/14 at 08:36am, Vivek Goyal wrote: > On Wed, Jun 11, 2014 at 08:39:05PM +0800, Baoquan He wrote: > > sudo makedumpfile -E -d 31 --vmcore-estimate /proc/kcore /var/crash/kcore-dump > > > > Questions: > > 1. Or we can get the dumpable page numbers only, then calculate the estimated > > vmcore size by a predifined factor if it's kdump compressed dumping. E.g if > > lzo dump, we assume the compression ratio is 45%, then the estimate size is > > equal to: (dumpable page numbers) * 4096* 45%. > > I think that we can probably not guess the saving from compression. > Compression ratio varies based on content of page. So if we keep it simple > and just calculate the number of pages which will be dumped and multiply > it by page size, that number will be much more accurate (for current > system). Yeah, this is another plan. Then the output will be the size of elf dump. If user configured the kdump compression, such as lzo/snappy, they can just estimate it by themselves. It's OK if user can accept this since this is much more accurate. Hi Anders, Do you have any comments on this? I found you are concerned with this issue too. Thanks Baoquan
