>> Just to note again: >> Ordinary 127MB btrfs gives "Out of space" around 64MB payload. 128MB is >> usable to the end.
> Thanks, and just to clarify for others possibly following along or > googling it up later, that's single mode (as opposed to dup mode) for at > least data, if in normal separate data/metadata mode, and single for the > combined mixed-mode chunks if in mixed-bg mode, correct? > > Because if the data is dup mode as well, as it would be by default in > mixed-bg mode (unless on ssd), 128 MiB should allow storing only 64 MiB > (and that's not accounting for the system chunk or global reserve > metadata, so it'd be less than that) data. That's /boot on my laptop. Its fairly old fs which is created about 3-4 years. May be 5. I'm not so sure.. btrfs filesystem df /boot System, single: total=4.00MiB, used=4.00KiB Data+Metadata, single: total=124.00MiB, used=103.88MiB GlobalReserve, single: total=4.00MiB, used=0.00B IT IS SINGLE!! The 128/64Mb thing happened when I created a backup usb drive for mirroring it. Then make it 256MB. btrfs filesystem df /mnt/back/boot Data, single: total=8.00MiB, used=0.00B System, DUP: total=8.00MiB, used=16.00KiB Metadata, DUP: total=32.00MiB, used=112.00KiB GlobalReserve, single: total=16.00MiB, used=0.00B IT IS DUP!! So Duncan you got it: I'm comparing the SINGLE to DUP... I'm not sure how I got that SINGLE though... >> I'm experimenting with an extracted (and customized) initrd on /boot. >> That is, /boot is a "minimal root on its own" which can switch to real >> root or do other things. Kernel and modules at /boot will not support >> any fs other than btrfs. (Or it may) >> It seems a minimally usable root around 10MB is possible. >> And it is free of udev and systemd.. > > You don't specifically mention the distro, but given that gentoo's one of > the only general-purpose distros that hasn't switched to systemd yet (tho > it offers the choice for those who want it, and I've taken that choice > here), there's a fair chance that's what you're running, as both I and > Martin Steigerwald (based on earlier threads) are. Now the offtopic: - I'm on Arch. Considering to switch to Void. - Using syslinux as bootmanager. It is rock solid and compact. Just edit syslinux.cfg and reboot to any configuration without any hassle. - Also using runit side stepping systemd. It is also rock solid and compact. - Know your hardware and thus the Kernel. And get rid of and middleware (all udev derivatives) playing guess games on your machine. - Two custom kernel configurations: All built-in (Was using until now.) All modules. (Now switching to this.) Load all your modules on exactly known locations when booting. To do this customize your runit start up scripts. I'm switching to "All modules" approach after I determined and understand the key modules. Don't affaid. Its accually very doable. You need at most 8-9 modprobes to get them all. If you know your HW and kernel it is no big deal. - Configuring kernel teaches alot. - Compiling a kernel with only required modules takes about 15 minutes if you got your .config file right. Play with "make xconfig". Alot... - Keep all your previous .config files as record. When something goes wrong diff them for throubleshooting. - Dracut is a dirty hack. mkinitcpio is great. - Compressed initrd is bad. It hides what is going on. Extract it. Play with it. Than make it the root fs of your /boot. (I'm now here) - Starting X without udev is simple. Disable hotplug. 5-6 lines of Manual entries for keyboard, mouse and touchpad is sufficient in your /etc/X11/xorg.conf.d -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
