Is there any workaround to the nanoBSD flash alignment issue?



  • Hi,

    I just tried installing pfSense on my shiny new (well new to me at least) Igel 5/4 thin client. It has a CF slot right on the main board so I followed the install instructions and wrote the nanobsd-vga image to my kingston 4GB CF card.

    Boot up seemed to go fine then hung after detection of my usb keyboard, oh no  :( - some 90 seconds later it finally finished booting.

    I seem to have the exact issue described here. Unusably slow performance due to mis alignment of the nanobsd partition images. There is a related bug here

    Performance is really bad - I could log in to the web interface but it then timed out trying to start the configuration wizard. Anything that touches the disk either times out or takes  30-60 seconds or more to complete. I can't even begin to imagine doing a full configuration of my firewall rules with those sorts of delays.

    Have I diagnosed the problem correctly? My CF card isn't anything special but I think this can't be right:

    [2.3-RELEASE][admin@pfSense.localdomain]/root: iostat -dt IDE
                ada0
      KB/t tps  MB/s
      6.08  11  0.06
    
    

    That is after disabling DMA mode in my bios (as per the Boot troubleshooting instructions) which boosted the transfer rate from 0.04 MB/s

    Is the only workaround to do a full, non embedded install? Can the full install be configured easily to avoid disk writes like the nanobsd version? I don't want to wear out the CF card in a couple of months, if this isn't fixable it's a showstopper before I even start experimenting with pfSense :(

    Any advice/encouragement welcome.



  • @drbob:

    Can the full install be configured easily to avoid disk writes like the nanobsd version? I don't want to wear out the CF card in a couple of months, if this isn't fixable it's a showstopper before I even start experimenting with pfSense :(

    Check out System / Advanced / Miscellaneous / Ram Disk Settings

    Also you may want to do a custom install and create a 3.5GB partition with no swap.  You don't want swap for obvious reasons, and leaving a little extra unused space leaves more blocks free for the controller to work with.



  • Thanks for the tip. I'll try that next. I also tried manually creating some 4k aligned partitions on my CF card and using dd to copy the partition contents form the nanobsd image in to them. This made no appreciable difference to performance.

    Further investigation led to what I believe is the cause of the performance problem - remounting the root partition as read only after it's been mounted as writeable takes around 40 seconds. This matches reports on bug 2401, which I guess has regressed. However I was also seeing some weird issues at the shell prompt where any command would lock the system for a long time before executing so that may not be the whole story.

    I've given up on the nanobsd image and I've ordered an ide ssd to use with the main version, though it's pretty miserable that the nanobsd image is effectively unusable due to this bug.



  • Two things:

    • System > Advanced > Miscellaneous: make sure "Use RAM Disks (x) Use memory file system for /tmp and /var" is checked
    • Diagnostics > NanoBSD: make sure "Permanent Read/Write (x) Keep media mounted read/write at all times" is ckecked and press Save.


  • @robi:

    Two things:

    • Diagnostics > NanoBSD: make sure "Permanent Read/Write (x) Keep media mounted read/write at all times" is ckecked and press Save.

    Thank you, this seems to have fixed all the issues (including the hangs at the shell prompt, my guess is pfsense was interrupting access to the filesystem with a remount causing the delays).

    I would never have found option that by hunting through the menus, especially as every page load was taking nearly a minute.

    I suspect that something is broken in the nanobsd config, why should it need to remount the disk read/write when navigating from menu to menu having made no change?



  • It's not broken.
    Search through the forums, been discussed 1000x.


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