Description of problem: The shipped document "kexec-kdump-howto.txt" claimed it supported VFAT or MSDOS partition as a target to save vmcore. However, it did not work, ... Freeing unused kernel memory: 320k freed Mounting proc filesystem Mounting sysfs filesystem Creating /dev Creating initial device nodes SCSI subsystem initialized Loading sd_mod.ko module Loading libata.ko module Loading ipr.ko ipr: IBM Power RAID SCSI Device Driver version: 2.2.0.2 (September 26, 2007) ipr 0000:01:01.0: Found IOA with IRQ: 26 module ipr 0000:01:01.0: Initializing IOA. ipr 0000:01:01.0: Starting IOA initialization sequence. ipr 0000:01:01.0: Adapter firmware version: 06160018 ipr 0000:01:01.0: IOA initialized. scsi0 : IBM 572E Storage Adapter Vendor: IBM-ESXS Model: ST973401SS Rev: B516 Type: Direct-Access ANSI SCSI revision: 05 SCSI device sda: 143374000 512-byte hdwr sectors (73407 MB) sda: Write Protect is off SCSI device sda: drive cache: write through w/ FUA SCSI device sda: 143374000 512-byte hdwr sectors (73407 MB) sda: Write Protect is off SCSI device sda: drive cache: write through w/ FUA sda: sda1 sda2 sda3 sd 0:0:1:0: Attached scsi disk sda scsi: unknown device type 31 Vendor: IBM Model: 572E001 Rev: 0150 Type: Unknown ANSI SCSI revision: 00 Loading jbd.ko module Loading ext3.ko module Loading dm-mod.kodevice-mapper: uevent: version 1.0.3 device-mapper: ioctl: 4.11.5-ioctl (2007-12-12) initialised: dm-devel module Loading dm-log.ko module Loading dm-mirror.ko module Loading dm-zero.ko module Loading dm-snapshot.ko module Waiting for required block device discovery Waiting for sda...Found Waiting for sda...Found Creating Block Devices Creating block device ram0 Creating block device ram1 Creating block device ram10 Creating block device ram11 Creating block device ram12 Creating block device ram13 Creating block device ram14 Creating block device ram15 Creating block device ram2 Creating block device ram3 Creating block device ram4 Creating block device ram5 Creating block device ram6 Creating block device ram7 Creating block device ram8 Creating block device ram9 Creating block device sda Making device-mapper control node Scanning logical volumes Reading all physical volumes. This may take a while... Found volume group "VolGroup00" using metadata type lvm2 Activating logical volumes 2 logical volume(s) in volume group "VolGroup00" now active Saving to the local filesystem /dev/VolGroup00/LogVol01 fsck.vfat: not found mount: Mounting /dev/VolGroup00/LogVol01 on /mnt failed: No such device umount: Couldn't umount /mnt: Invalid argument [: 0: unknown operand Attempting to enter user-space to capture vmcore ... From the resulted init file in the initramfs, ... fsck.vfat $DUMPDEV mount -t vfat $DUMPDEV /mnt if [ $? == 0 ] then mkdir -p /mnt//var/crash/127.0.0.1-$DATE VMCORE=/mnt//var/crash/127.0.0.1-$DATE/vmcore export VMCORE monitor_cp_progress $VMCORE-incomplete & cp /proc/vmcore $VMCORE-incomplete >/dev/null exitcode=$? if [ $exitcode == 0 ] then mv $VMCORE-incomplete $VMCORE echo -e "\\033[0JSaving core complete" fi fi ... Looks like necessary module was not included in Kdump initramfs. Even if the required module has been loaded manually using, extra_modules vfat It still failed because the target directory's name is too long, ... Activating logical volumes 2 logical volume(s) in volume group "VolGroup00" now active Saving to the local filesystem /dev/VolGroup00/LogVol01 fsck.vfat: not found mkdir: Cannot create directory `/mnt//var/crash/127.0.0.1-2008-10-07-02:44:57': Invalid argument cp: unable to open `/mnt//var/crash/127.0.0.1-2008-10-07-02:44:57/vmcore-incomplete': No such file or directory Attempting to enter user-space to capture vmcore ... Version-Release number of selected component (if applicable): kexec-tools-1.102pre-21.el5 kexec-tools-1.102pre-44.el5 How reproducible: always Steps to Reproduce: 1. create a VFAT partition - mkfs.vfat /dev/VolGroup00/LogVol01 2. configure the Kdump - vfat /dev/VolGroup00/LogVol01 3. SysRq-C
I'm not sure where you saw the included documentation claim tha vfat and msdos were supported. From kexec-kdump-howto.txt: Note that for local file systems ext3 and ext2 are supported as dumpable targets. Kdump will not prevent you from specifying other filesystems, and they will most likely work, but their operation cannot be guaranteed. for instance specifying a vfat filesystem or msdos filesystem will result in a successful load of the kdump service, but during crash recovery, the dump will fail if the system has more than 2GB of memory (since vfat and msdos filesystems do not support more than 2GB files). Be careful of your filesystem selection when using this target. I thought that was pretty clear in saying that you can try other filesystems, but only ext2/3 were officially supported. If there is something to further clarify that, please suggest it and I'm happy to add it in. I've had a request for vfat & msdos previously, and we can fix the module loading if you think its a good idea, but honestly, vfat and msdos simply aren't going to be supported for dump capture. Between size limitations and name formatting limitations, its simply not feasible.
OK, thanks for pointing out. I should read the document more carefully.