Am 23.04.2012 06:11, schrieb Cong Wang: > On Fri, 2012-04-20 at 09:51 -0400, Vivek Goyal wrote: >> On Thu, Apr 19, 2012 at 10:59:17AM +0200, Harald Hoyer wrote: >>> Am 19.04.2012 00:28, schrieb Vivek Goyal: >>>> Hi, >>>> >>>> I am trying to dump kernel vmcore to an software iscsi target (kdump). >>>> kdump specifies the dump destination using "--mount" option. But dracut >>>> does not even include the "iscsi" module and associated device is not >>>> mounted in second kernel. >>>> >>>> Following is the dracut command line as called by /sbin/mkdumprd. >>>> >>>> dracut -m kdumpbase --add dash --add fstab-sys --add kernel-modules -c /dev/null -I /sbin/makedumpfile --mount '/dev/mapper/vg-lv_root / ext4 rw,seclabel,relatime,user_xattr,barrier=1,data=ordered' --mount '/dev/mapper/mpatha /mnt/common ext4 rw,seclabel,relatime,user_xattr,barrier=1,stripe=16,data=ordered' -M -f /boot/initramfs-3.3.2-1.fc17.x86_64kdump.img 3.3.2-1.fc17.x86_64 >>> >>> "-m kdumpbase" - This tells dracut to only use the kdumpbase dracut module >>> So, because the iscsi dracut module is not added, dracut does not even check() it. >>> >>> Why is it "-m kdumpbase" and not "--add kdumpbase" ??? >> >> I don't know why -m is being used instead of --add. I tried changing it >> to --add and uncompressed initramfs size changed from 36MB to 72MB. >> >> To me 32MB size itself is big. IIRc, in RHEL6 using our own mkinitrd, we had >> uncomressed initrd size close to 25MB. >> >> In kdump environment we work in very restricted memory conditions. >> Currently we reserve 128MB and there are calls to reduce it further. This >> 128MB should load kernel, initramfs and run all the tools in initramfs >> to actually save the vmcore to the target. >> >> So we need to figure out how can we reduce the size of initramfs for >> kdump case. In the next mail I will add the output of --debug both for >> -m kdumpbase and --add kdumpbase. >> >> From kdump perspective, we only need to mount targets as specified by >> --mount option. We might not want to mount even root and it depends on >> kdump.conf. If root is needed, we will pass that too on command line >> using --mount. So this is little different from -H option. >> >> Can we modify dracut in such a way so that it packs only those modules >> need to mount targets as specified --mount options? > > Yeah, I noticed this too, I think this is due to the dracut module > "kernel-modules" includes more than enough kernel modules into > initramfs, thus the size increased so much. > > Harald, if you have any idea to improve this? We need to find a way to > tell "kernel-modules" module to only include the ones we want. Just activate the host-only mode "--hostonly" or "-H" > > Thanks. > -- To unsubscribe from this list: send the line "unsubscribe initramfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
