Hello Axel, On 2020-02-24 T 11:41 +0100 Axel Braun wrote:
Am Sonntag, 23. Februar 2020, 22:36:33 CET schrieb Matthias G. Eckermann:
On 2020-02-23 T 17:03 +0100 Axel Braun wrote:
Except that I feel that one should not use btrfs on a 32GB SD card
one of the reasons to use btrfs for the RPi image (I know that at least for SUSE Linux Enterprise) is that it is compressed and thus the low IO-throughput of the SD card interface is accelerated; assuming a compression rate for the OS part of more than 30%, the performance factor should be similar for reads and writes.
Thanks for the information!
So the old rule (i remember some discussions on the factory mailing list from some time ago) that btrfs on less than 40GB is not recommended, is not valid any longer?
well. I would have never called this "40GiB" a "rule", but more a "recommendation" for a btrfs root filesystem *with* snapshots enabled, and this recommendation has a *lot* of safety buffer included. Mind that this heavily depends on the - distribution and - your personal way of applying updates. To add some details: * For a Tumbleweed with add-hoc updates enabled, I would rate 40 GiB the lower limit, indeed, better more, as you have a lot of change, thus lots of snapshots and lots of metadata. * For a Leap or SUSE Linux Enterprise with, let's say, planned weekly updates, you can easily work with a btrfs filesystem as small as twice the size of the OS installation, or for an extra buffer three times: MINIMAL_SIZE=$(( 3* $( du -msx / | cut -d'/' -f1) )) I personally run (all my) systems with a 32 GiB root filesystem with snapshots enabled, and the number of snapshots limited to 8 in total. That said, for a Raspberry Pi and an SD card, I would recommend to apply updates rather carefully and not in tumbleweed style, because the SD card might not like this too much:-/ Thus, a 32 GiB filesystem (with compression enabled this is equivalent to 42 GiB or more effectively) should be very comfortable. Hope this helps. So long - MgE -- Matthias G. Eckermann, Director Product Management Linux Platforms SUSE Software Solutions Germany GmbH - Maxfeldstr. 5 - 90409 Nürnberg (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer -- To unsubscribe, e-mail: opensuse-arm+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-arm+owner@opensuse.org