Hi, Thought experiment time... I have an HP z820 workstation here (with ECC memory, yay!) and 4x250G 10k SAS disks (and some spare disks). It's donated hardware, and I'm going to use it to replace the current server in the office of a non-profit organization (so it's not work stuff this time). The machine is going to run Debian/Xen and a few virtual machines (current one also does, but the hardware is now really starting to fall apart). I have been thinking a bit how to (re)organize disk storage in this scenario. 1. Let's use btrfs everywhere. \:D/ 2. For running Xen virtual machines, I prefer block devices on LVM. No image files, no btrfs-on-btrfs etc... 3. Oh, and there's also 1 MS Windows VM that will be in the mix. Obviously I can't start using multi-device btrfs in each and every virtual machine (a big pile of horror when one disk dies or starts misbehaving). So, what I was thinking of is: * Use dm-integrity on partitions on the individual disks * Use mdadm RAID10 on top (which is then able to repair bitrot) * Use LVM on top * Etc... For all of the filesystems, I would be doing backups to a remote location outside of the building with send/receive. The Windows VM will be an image file on a btrfs filesystem in the Xen dom0. It's idle most of the time, and I think cow+autodefrag can easily handle it. I'd like to be able to take snapshots of it which can be sent to a remote location. Now, to finally throw in the big question: If I use btrfs everywhere, can I run dm-integrity without a journal? As far as I can reason about.. I could. As long as there's no 'nocow' happening, the only thing that needs to happen correctly is superblock writes, right? -- Hans van Kranenburg
