Dear Proxmox developers, I hope it is fine to report this here, otherwise I can repost on pve-user.
I initially noticed that backup/restore has a bug when the disk size is not a multiple of 64K for DRBD devices. Due to DRBD meta-data the user visible size is almost certainly not 64K aligned. But this is not limited to DRBD and fairly easy to reproduce on plain LVM. Files used to reproduce can be found here[1]. - create a VG that is 1k aligned as in "vgcreate -s 1k backup /dev/whatever" - add it to /etc/pve/storage.cfg I created the storage via the GUI, there might be an easier CLI way: - create a VM on the 1k aligned storage with 1 (GB) of space. Everything else was set to defaults. - lvextend -L +4k /dev/backup/vm-100-disk-0 # GUI still shows an even 1GB - extend the disk via the GUI (1 additional GB); now the GUI shows 2097156K - zcat /tmp/breaksmox.img.gz - | dd of=/dev/backup/vm-100-disk-0 \ ;sync;sync;sync >From that I created a backup (also via the GUI), all defaults except no compression. On "vma verify" this fails: vma verify /tmp/breaksmox.vma vma: verify failed - got wrong block address - write beyond end Trace/breakpoint trap For me every install of an Alpine Linux on such an "unaligned" disk triggers this bug (I always did a zero out before the install). The image from [1] is just zero outed at the beginning after the install to reduce the size. I did not try to minimize that, I just zeroed a bit less than 2GB of the installed image. Here some observations where I *think* things go wrong: The interesting part is here: xxd -s 301568 /tmp/breaksmox.vma If you look at this last VMA Extent Header, the block info with number 0x8000 has a mask of 0xe1fe, and garbage data. I don't think there should be this (random) garbage at the end. What is also also slightly worrisome is that I had images/backups where the garbage part of the backup contained data that could not be found in the image itself, so most likely this also leaks host memory to the backups. Failing for non 64K aligned disks was also reported here[2]. Best, rck [1] https://packages.linbit.com/rck/breaksmox/ [2] https://forum.proxmox.com/threads/how-do-i-restore-a-vm-with-a-non-64k-block-disk.58863/ _______________________________________________ pve-devel mailing list pve-devel@pve.proxmox.com https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
