https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230903
Bug ID: 230903
Summary: remount root readonly slow on Alix
Product: Base System
Version: 11.2-STABLE
Hardware: Any
OS: Any
Status: New
Severity: Affects Only Me
Priority: ---
Component: kern
Assignee: [email protected]
Reporter: [email protected]
Hey,
On this Alix machine, mounting root readonly after mounting it read-write is
slow, as in:
% mount -w /
% time mount -r / # 15-20 seconds
A workaround is to mount the partition async in which case the remount is
almost instant. My typical workflow is to mount read-write, break something,
then remount read-only for the sake of fsck(8).
The original Alix series use a Compact Flash -> ATA controller. I've observed
this behavior with multiple CF cards. Typical WCHAN is `biowr', `wdrain' or
both. This behavior persists since at least FreeBSD 10 series.
Note, the CF storage isn't that slow, see:
cat /usr/lib/* > /dev/null 0.10s user 1.21s system 46% cpu 2.821 total
cat /usr/bin/* > /dev/null 0.12s user 3.09s system 67% cpu 4.756 total
There are some nasty things in KERNCONF, only to reduce logspam and save time
otherwise spent probing for nonexistent controllers. The Alix series have none
of these controllers:
-->--
include GENERIC
[trivia]
nooptions SMP
nooptions APIC_IO
nodevice acpi
nodevice xenpci # fix build
nooptions XENHVM # idem
nodevice hyperv # idem
--<--
I can attach various config files (sysctl.conf, rc.conf, dmesg.boot, fstab,
KERNCONF) if necessary but they look sane other than the aforementioned
KERNCONF.
cheers,
sh
--
You are receiving this mail because:
You are the assignee for the bug.
_______________________________________________
[email protected] mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-bugs
To unsubscribe, send any mail to "[email protected]"
