Re: AFS on FreeBSD 8?

Jan Henrik Sylvester <[email protected]> Thu, 20 May 2010 19:19:52 +0200
Newsgroups gmane.os.freebsd.devel.afs
Message-ID <[email protected]>
On 05/18/10 20:14, Derrick Brashear wrote:
> On Tue, May 18, 2010 at 1:54 PM, Jan Henrik Sylvester<[email protected]>  wrote:
>> On amd64, the listing of the directories was instant unlike on i386. Reading
>> (small) files caused no problems, but I was able to crash the machine
>> accessing some weird entry (some object that OpenAFS on Linux shows with "?"
>> for the file permissions) and -- more realistically -- deadlock all access
>> to afs upon trying to copy a large file to afs.
>
> does
> cmdebug (yourhost)
> return anything?

- change to some afs-directory
cmdebug: nothing
- change to some afs-directory that uses krb login
cmdebug: crashes the machine instantly
- repeat both steps after reboot
cmdebug: nothing
- copying a small file
cmdebug: reports something (I lost it, looked as if it was expected)
- eventually copying of the small file finished (took very long)
cmdebug: nothing
- copying a large file
cmdebug: nothing
- copying takes forever (does nothing after a second, no reading)
cmdebug: nothing

>>> I expect that you will find AFS more usable if you set
>>> kern.smp.disabled=1 in /boot/loader.conf, which will make your machine
>>> effectively single-processor.
>>
>> I just tried that and copying a large file to afs caused a deadlock of afs,
>> too. I guess it is not just SMP.

The "protocol" above was with SMP enabled. I could repeat it with SMP 
disabled if you expect anything from it. (I did observe the same 
behavior with SMP disabled.)

On a different machine, I was just changing afs directories and listing 
them calling cmdebug a few times in between. Nothing happened, but when 
I came back to the machine a few minutes later, it had deadlocked 
completely -- without copying data at all.

I just found the first machine that I tried to reboot with its stalled 
copy process is now hanging completely, too.

I would have tried to narrow down the circumstances that cause 
deadlocks, if both of the machines in front of me were not crashing so 
often...

Cheers,
Jan Henrik
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