zfs sector size on proxmox installation

efeu

Renowned Member
Nov 6, 2015
91
8
73
Hi,
how can I set a different sector size for zfs on proxmox installation? As I read somewhere it's always set to ashift=12 aka 4k blocksize. I want to set it to 8k (ashift=13) and on another node to 32k (ashift=15?).
 
it is currently hard coded to 12. could you file an enhancement request at bugzilla.proxmox.com ? I'll see whether we can include this in the next version of the installer..
 
I do not understand you clearly, you mean I should send a mail to the bug assignees? So even in debug installation it is not possible to set the correct zfs blocksize?
 
the debug mode drops you to a shell at various stages of the installer, but it is mainly there to investigate when things don't work. the ashift value is hardcoded in the installer source, which is not changeable in debug mode.

until this is configurable in the installer, you have these options:
  • don't use ZFS on / , but manually create a "data" zpool after installation (easiest)
  • install with ZFS on / with ashift=12, then zfs send/receive whole pool to a manually created pool with your desired ashift and swap disks (requires additional hardware and a bit of ZFS/Grub2 knowledge, depending on pool configuration)
  • install with ZFS on / with ashift=12 and live with it (probably not desired)
  • install Debian Jessie with ZFS on / with desired ashift, install PVE on top (very complicated and not supported)
I know this is inconvenient - please file a a new bug at https://bugzilla.proxmox.com so that it is tracked and not forgotten.
 
Almost one year ago I posted the problem and suggestion how to improve proxmox installation https://forum.proxmox.com/threads/proxmox-install-script.25120/

It seems like this was missed / overlooked - since you already had quite concrete ideas on how to fix the issues you encounter, it might have been better to post this to pve-devel (or even try to create patches for the installer and post them ;)). The second issue with different hard disk sizes was recently filed as a bug and is already fixed in git (although the fix uses a different approach and simply allows up to 10% size difference when creating mirrors, which would not have helped in your case).

The problem with your proposed solution is that you cannot specify properties multiple times when calling zpool, but it should be easy enough to find a solution for this.

So I created a bug report, if I did miss something feel free to add comments.
https://bugzilla.proxmox.com/show_bug.cgi?id=1201

No, that is enough for now. I will update the bug when there is progress!
 

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