Hi,
I guess Volkmar is quite right suspecting AFS cache file system issues
as the cause of your problem.
Sorry can't hellp with that, but another cache configuration might help.
We made good experiences to put the AFS cache on a tmpfs in swap which
finally is held by the OS in memory.
This requires an entry in /etc/vfstab (on Linux it's /etc/fstab) looking
like follows:
#device device mount FS fsck
mount mount
#to mount to fsck point typepass
at boot options
#
...
swap- /var/afs-cache tmpfs -
yes size=16384m
This kind of AFS configuration works like a disk cache (no need to
modify your afsd startup parameters),
but provides speed like a memcache because tmpfs is managed in memory as
long as some is available.
I should say our OS environment is Solaris 10 and 11. However, should
work on Linuxes very similar.
Regards,
Karl
On 06.10.16 13:31, Volkmar Glauche wrote:
Hi Michael,
I don't know what is going on in detail here. Since the kernel log says
something about AFS cache scan before the crash, there might be some
issue with your cache partition. If your overlay covers the entire
client filesystem, does that include AFS cache as well? Would it be
possible to either mount a non-overlay partition for the cache (disk or
ram)? Another workaround might be to use a memory cache instead of a
disk cache.
Best,
Volkmar
Am Donnerstag, den 06.10.2016, 09:20 + schrieb Richter, Michael:
Hi,
I’m using Ubuntu 12.04 on ~240 computers for years with this
configuration without problems. I’m now trying to migrate to Ubuntu
16.04. Ubuntu is booted with readonly filesystem. A initramfs script
sets an union fs on top to bring write access. Nearly the same as on
every live CD.
On top there is the OpenAFS client. Which connects the users home
share on log on. But the OpenAFS client crashes on system boot.
If I disable OpenAFS completely and use accounts from another domain
without OpenAFS share, everything works. If I don’t use the overlay
and mount the drive read/write OpenAFS is working too. Only the
combination of OpenAFS and OverlayFS (or AuFS) is not working.
I also tried Ubuntu‘s Upstream Kernel and the OpenAFS client from
OpenAFS website. Nothing helped.
This is what I do in initramfs‘ init-bottom script:
~~~
ro_mount_point="${rootmnt%/}.ro"
rw_mount_point="${rootmnt%/}.rw"
echo Create mount points for the read-only and read/write layers:
mkdir "${ro_mount_point}" "${rw_mount_point}"
echo Move the already-mounted root filesystem to the ro mount point:
mount --move "${rootmnt}" "${ro_mount_point}"
echo Mount the read/write filesystem:
modprobe -r zram
modprobe zram num_devices=4
echo 1 > /sys/block/zram0/reset
echo lz4 > /sys/block/zram0/comp_algorithm
echo 2 > /sys/block/zram0/max_comp_streams
echo 3G > /sys/block/zram0/disksize
mke2fs /dev/zram0
mount -t ext2 /dev/zram0 "${rw_mount_point}"
# also tried tmpfs here
#mount -t tmpfs -o rw,noatime,mode=755 root.rw "${rw_mount_point}"
mkdir "${rw_mount_point}/upper"
mkdir "${rw_mount_point}/work"
echo Mount the union:
mount -t overlay -o
"lowerdir=${ro_mount_point},upperdir=${rw_mount_point}/upper,workdir=
${rw_mount_point}/work" overlay "${rootmnt}"
mkdir "${rootmnt}/ro" "${rootmnt}/rw"
mount --bind "${ro_mount_point}" "${rootmnt}/ro"
mount --bind "${rw_mount_point}" "${rootmnt}/rw"
~~~
I also attached the crash part from kern.log.
Do someone know how to get this working? Is it a bug? Am I doing
something wrong?
Michael Richter
--
Michael Richter
Technische Universität Berlin
Universitätsbibliothek
IT-Service
Fasanenstraße 88, 10623 Berlin
Telefon: +49 (0)30 314-76310
m.rich...@tu-berlin.de
www.ub.tu-berlin.de
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--
Dr. Karl Behler
CODAC & IT services ASDEX Upgrade
phon +49 89 3299-1351 fax 3299-961351
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