Currently kdump is not working well with encrypted targets, add document about this issue.
Signed-off-by: Kairui Song kasong@redhat.com --- kexec-kdump-howto.txt | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt index fa01a3d..b4164af 100644 --- a/kexec-kdump-howto.txt +++ b/kexec-kdump-howto.txt @@ -684,6 +684,20 @@ a machine with a disk image which have kdump initramfs embedded, you should rebuild the initramfs using "kdumpctl rebuild" command manually, or else kdump may not work as expeceted.
+Notes on encrypted dump target: + +Currently, kdump is not working well with encrypted dump target. +First, user have to give the password manually in capture kernel, +so a working interactive terminal is required in the capture kernel. +And another major issue is that an OOM problem will occur with certain +encryption setup. For example, the default setup for LUKS2 will use a +memory hard key derivation function to mitigate brute force attach, +it's impossible to reduce the memory usage for mounting the encrypted +target. In such case, you have to either reserved enough memory for +crash kernel according, or update your encryption setup. +It's recommanded to use a non-encrypted target (eg. remote target) +instead. + Parallel Dumping Operation ========================== Kexec allows kdump using multiple cpus. So parallel feature can accelerate
On 05/10/19 at 03:11pm, Kairui Song wrote:
Currently kdump is not working well with encrypted targets, add document about this issue.
Signed-off-by: Kairui Song kasong@redhat.com
kexec-kdump-howto.txt | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt index fa01a3d..b4164af 100644 --- a/kexec-kdump-howto.txt +++ b/kexec-kdump-howto.txt @@ -684,6 +684,20 @@ a machine with a disk image which have kdump initramfs embedded, you should rebuild the initramfs using "kdumpctl rebuild" command manually, or else kdump may not work as expeceted.
+Notes on encrypted dump target:
+Currently, kdump is not working well with encrypted dump target. +First, user have to give the password manually in capture kernel, +so a working interactive terminal is required in the capture kernel. +And another major issue is that an OOM problem will occur with certain +encryption setup. For example, the default setup for LUKS2 will use a +memory hard key derivation function to mitigate brute force attach, +it's impossible to reduce the memory usage for mounting the encrypted +target. In such case, you have to either reserved enough memory for +crash kernel according, or update your encryption setup. +It's recommanded to use a non-encrypted target (eg. remote target) +instead.
Parallel Dumping Operation
Kexec allows kdump using multiple cpus. So parallel feature can accelerate
2.20.1
Ack
Thanks Dave
-
Dave Young -
Kairui Song