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About dkxls

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  1. Thanks @Steven Keuchel for clarifying this. I am currently running zfs 0.7.12 with the default memory settings on my helios4 and haven't encountered any issues yet. Regarding zfs 0.8, it would be good if you could post your experience with the patched version from zfsonlinux/zfs#9967 in that PR to get more feedback on the changes. We also still need zfs test results from other ARM 32-bit systems to establish a baseline before this can get merged.
  2. @SvenHz I made some progress on tracking down this issue with zfs 0.8 on the Helios4, more precisely James Robertson (@jsrlabs) identified and fixed the missing Thumb-2 instructions used by the Armbian kernel, see the discussion on the ZFS mailinglist. I went ahead and opened a bug report (zfsonlinux/zfs#9957), and one of the zfs developers proposed a fix in this pull request: zfsonlinux/zfs#9967. However, the fix needs testing, so I thought to bring this up here in the hope that someone else will give this a shot as well.
  3. I finally got ZFS installed on my Helios4 using Armbian 19.11.3 Buster with Linux 4.19.84, but I had to stick with ZFS version 0.7.12, as advise by @SvenHz in this post. Loading the ZFS 0.8 module would fail with the same error. @Steven Keuchel Thanks again for your input on the kernel/ZFS memory settings. I had a more detailed look at your settings and noticed that you set `zfs_arc_max=805306368` (i.e. to 768 MB), which corresponds to the maximum `vmalloc` you seem to use. Or were those ZFS settings with `CONFIG_VMSPLIT_2G` and you use in fact an even higher value for `vmalloc`? Which ZFS version did you use, 0.6 or 0.7? As @qstaq stated, the default for `zfs_arc_max` is 50% of the available memory. There is however a pull request to increase this even further to 3/4 of all memory or all but 1GB, whichever is greater. This change is enabled due to the revised memory allocation for the ARC buffers in ZFS version 0.7. In fact, this change makes me wonder if those settings for `vmalloc` and `zfs_arc_max` still make sense for ZFS >= 0.7. The fundamental issue with the extensive use of the virtual address space in ZFS was outlined rather well by one of the developers in this ZOL issue. This was addressed however in version 0.7 with the introduction of the ARC Buffer Data (ABD), as also mentioned in the ZFS 0.7 release notes. It appears that the issues with the virtual address space are limited to ZFS versions 0.6 and older. Or is my understanding of this incorrect? Any advice or comment in this regard would be greatly appreciated.
  4. @gprovost Sure. I wasn't aware that you accept community contributions to the wiki. I might take a stab at that once I have my own setup working ... If someone else, probably more experienced with ZFS, is up for that, please go ahead - I for one would certainly appreciate it.
  5. @Steven Keuchel sorry for my late reply and thanks a lot for your advice regarding the kernel memory configuration. Much appreciated! I will probably start with a readily available kernel and set the correct parameters as suggested, and will later on look into compiling my own kernel. Do you have any advice regarding the compilation, any pointer to documentation or even a config file would be greatly appreciated here. @SvenHz Thanks for sharing your experience with zfs 0.8.2! I will stick to the 0.7 series if at all possible then for now as well. I think it would be good to have some kind of a documentation/guidelines for setting up zfs on a Helios4, as currently all these information seem to be distributed and one needs to go through various forum threads to get this working. @gprovost Have you considered to put this to the Helios4 wiki, maybe marked as an advanced or experimental setup for people that are keen to tinker around with this kind of thing?
  6. dkxls


  7. @qstaq this sounds interesting. Would you be willing to share these scripts/settings either in public or private? I reckon this could be very useful, especially for beginners like me.