kdump/kexec vmcore size doubles each time

From: joe shmoe
Date: Thu Jul 19 2012 - 18:14:21 EST

I am trying to configure kexec/kdump on 2.6.35-14.

$> kexec --version
kexec-tools-testing 20080330 released 30th March 2007

I did manage to configure kdump to use raw device (/dev/sda7) for saving the dump from within the initrd.

When the production kernel boots, it copies core from /dev/sda7 to /var/crash/ path.
I see that the size of data copied over from /dev/sda7 to /var/crash almost doubles with every crash (370MB to 620MB to 1.2 GB to 2.1GB).

The size returns back to normal, should there be a "normal" reboot cycle anytime. After that every subsequent crash again doubles the size. This is very baffling.

On a related note, I wanted to understand if there are any known issues with having swap device as a dump location. Does kdump start
early enough to ensure that vmcore can be safely copied off swap
/dev/sda7 and THEN mkswap/swapon commands set up the swap space?

Thanks much.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/