[PATCH] Makedumpfile: vmcore size estimate
bhe at redhat.com
Mon Jun 23 06:05:33 PDT 2014
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
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.
Do you have any comments on this? I found you are concerned with this
More information about the kexec