Hello,
I'm new to this list, apologies if I'm asking something stupid..
We're using AUFS on a Debian 8 system to protect the root file system from
writes. The readonly layers are based on SquashFS and the top, rw layer is a
60 MB tmpfs.
Problem: When the tmpfs fills up (eg. `cat /dev/zero > /DUMMY`), then the
system consistently becomes pratically unusable, meaning that simple
commands like `find` or `reboot` can't be run anymore ("command not found").
I've also noticed some kernel errors (at least when running for some hours
in such a state), but they don't come up immediately:
Oct 31 15:31:01 intermodul kernel: [87752.031289] aufs au_xino_do_write:433:iog
et[14146]: I/O Error, write failed (-28)
Oct 31 15:31:01 intermodul kernel: [87752.031301] aufs au_xino_write:469:ioget[
14146]: I/O Error, write failed (-5)
Oct 31 15:31:01 intermodul kernel: [87752.050390] aufs au_xino_do_write:433:iog
et[14148]: I/O Error, write failed (-28)
Oct 31 15:31:01 intermodul kernel: [87752.050402] aufs au_xino_write:469:ioget[
14148]: I/O Error, write failed (-5)
# df
Filesystem 1K-blocks Used Available Use% Mounted on
none 65536 65536 0 100% / <-- AUFS mount
devtmpfs 10240 0 10240 0% /dev
/dev/sda2 14871 7760 6343 56% /mnt/boot
tmpfs 20480 4404 16076 22% /var/log
tmpfs 256012 0 256012 0% /dev/shm
tmpfs 256012 360 255652 1% /run
tmpfs 5120 0 5120 0% /run/lock
tmpfs 256012 0 256012 0% /sys/fs/cgroup
/dev/sda7 310114 3362 286221 2% /mnt/recovery
/dev/sda5 56389 2214 49803 5% /mnt/sys
/dev/sda6 237869 2356 218925 2% /mnt/user
The AUFS fs is mounted in a custom init script like this:
mount -t aufs -o noatime,br=/root-rw:/rom-2903377e5ff89eb40e7eb7697903ee71.sfs=
rr+wh:/rom-e4a850b9995d3d16555389e970fb2e77.sfs=rr+wh:/rom-b7c7293bab12f98812ff
f36f13e871b7.sfs=rr+wh:/rom-e14feb39ef838532fcffe4000e73a2db.sfs=rr+wh:/rom-5fd
b4e194d6ecdf56614da916ca29017.sfs=rr+wh:/rom-12dd0bbdc7bae45bc10fb79debc48ebd.s
fs=rr+wh:/rom-0e8deac60f973e93a1fc0562e0cc3b78.sfs=rr+wh none /newroot
After running that mount command, my mounts are as follows:
rootfs on / type rootfs (rw)
proc on /proc type proc (rw,noatime)
sysfs on /sys type sysfs (rw,noatime)
udev on /dev type devtmpfs (rw,relatime,size=10240k,nr_inodes=62128,mode=755)
/dev/disk/by-label/IM_BOOT1 on /rootfs-images type ext2 (ro,noatime)
tmpfs on /root-rw type tmpfs (rw,noatime,size=65536k)
/dev/loop0 on /rom-0e8deac60f973e93a1fc0562e0cc3b78.sfs type squashfs (ro,noati
me)
/dev/loop1 on /rom-12dd0bbdc7bae45bc10fb79debc48ebd.sfs type squashfs (ro,noati
me)
/dev/loop2 on /rom-5fdb4e194d6ecdf56614da916ca29017.sfs type squashfs (ro,noati
me)
/dev/loop3 on /rom-e14feb39ef838532fcffe4000e73a2db.sfs type squashfs (ro,noati
me)
/dev/loop4 on /rom-b7c7293bab12f98812fff36f13e871b7.sfs type squashfs (ro,noati
me)
/dev/loop5 on /rom-e4a850b9995d3d16555389e970fb2e77.sfs type squashfs (ro,noati
me)
/dev/loop6 on /rom-2903377e5ff89eb40e7eb7697903ee71.sfs type squashfs (ro,noati
me)
none on /newroot type aufs (rw,noatime,si=c0b516b)
`/newroot` is then used for `switch_root`.
Kernel: Linux intermodul 3.16.0-4-686-pae #1 SMP Debian 3.16.7-ckt11-1+deb8u3 (
2015-08-04) i686 GNU/Linux
Commandline: BOOT_IMAGE=/boot/kernel ro root=LABEL=IM_BOOT1 panic=10 quiet nmi_
watchdog=0 nomodeset
Any hints what's wrong?
Please let me know if I can provide any additional helpful information...
Thanks,
Udo
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