There is already documentation about it. For example, from https://ubuntu.com/server/docs/kernel-crash-dump
"If the dump does not work due to OOM (Out Of Memory) error, then try increasing the amount of reserved memory by editing /etc/default/grub.d/kdump-tools.cfg. For example, to reserve 512 megabytes" There are multiple reasons why an OOM might happen during kdump, and there are no plans on detecting them on a case-by-case, so we won't do it for this specific case of root volume decryption. If we use a very large default that might work on almost all cases, it will take much more memory than is necessary for many users. On the other hand, using a default that won't work for most users is not any better. So, noticing that any default will affect all users, including those that do not enable root volume encryption or do not use argon2i; we have 3 options for the new default: 1) Keep 2G-4G:384M; some users won't be able to collect kdump unless they reconfigure the crashkernel option, but most users will, by reserving not more than 384M from a 2G VM. 2) Raise it to 2G-4G: 512M, it reserves more memory, and users with 2G to 4G VMs using argon2i for root volume encryption might be able to collect kdump for the sake of reserving more memory by default for users that don't use root volume encryption. 3) Remove the 2G-4G section of crashkernel: users with VMs smaller than 4G won't be able to collect kdump unless they configure and test a crashkernel configuration by themselves. I still think the first option is the better one. Cascardo. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to makedumpfile in Ubuntu. https://bugs.launchpad.net/bugs/1877533 Title: [20.10 FEAT] Increase the crashkernel setting if the root volume is luks2-encrypted Status in Ubuntu on IBM z Systems: In Progress Status in kdump-tools package in Ubuntu: Invalid Status in makedumpfile package in Ubuntu: Invalid Status in kdump-tools source package in Focal: Invalid Status in makedumpfile source package in Focal: In Progress Status in kdump-tools source package in Groovy: Invalid Status in makedumpfile source package in Groovy: In Progress Bug description: Description: In case the volume containing the root filesystem is encrypted using LUKS2 the memory used while unlocking the volume may exceed the size allocated to the kdump kernel. This will lead to a failure while processing kdump and the dump file will not be stored. Unfortunately, this condition may not be detected by a client before a problem occurs. The request is to have the kdump package installation script check for LUKS2 encryption (more precisely for Argon2i PBKDF, which is the root cause of the high memory usage). If the condition is met, the installation procedure should increase the crashkernel parameter to a higher value (>=512M)or issue a warning, if the system memory is insufficient to reserve enough crashkernel memory. Business Case: Pervasive Encryption and Secure Execution require encryption of the filesystems in order to keep customer data secure at all times. With the increasing usage of these technologies, the number of kdump will rise too, typically at inconvenient times, when the kdump is triggered due to a real customer issue. With the suggested change, the number of customer complaints and effort to handle them will be reduced. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1877533/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
