On Tue, Jan 27, 2009 at 9:06 PM, Tyler <tyler_at_cryptio.net> wrote:
> On Tue, Jan 27, 2009 at 02:09:29PM +0100, Andreas Braathen wrote:
>> futex seems to be a fast lock mechanism in Unix? Can I for instance try
>> to turn of the locking to make
>> it "less reliable" for a period to check this theory?
>>
>> >open("/afs/project/db/__db.001", O_RDWR|O_CREAT|O_EXCL|O_LARGEFILE,
>> >0666) = -1 EEXIST (Fileexists)
>> >open("/afs/project/db/__db.001", O_RDWR|O_CREAT|O_EXCL|O_LARGEFILE,
>> >0666) = -1 EEXIST (Fileexists)
>> >open("/afs/project/db/__db.001", O_RDWR|O_CREAT|O_EXCL|O_LARGEFILE,
>> >0666) = -1 EEXIST (Fileexists)
>> >open("/afs/project/db/__db.001", O_RDWR|O_LARGEFILE) = 4
>> >fcntl64(4, F_SETFD, FD_CLOEXEC) = 0
>> >fstat64(4, {st_mode=S_IFREG|0644, st_size=16384, ...}) = 0
>> >close(4) = 0
>> >open("/afsproject/db/__db.001", O_RDWR|O_LARGEFILE) = 4
>> >fcntl64(4, F_SETFD, FD_CLOEXEC) = 0
>> >mmap2(NULL, 16384, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) = 0xb7cb7000
>> >close(4) = 0
>> >futex(0xb7cb7000, FUTEX_WAIT, 2, NULL
>
> Maybe someone understands this more deeply than I do but I think you're
> on the right track here. The fact that you say you haven't changed
> anything else in your workflow definitely makes me want to dig into the
> network-mounted filesystem as the source of the problems.
>
> Turning off hard locks is a good starting point.
>
> There's also a million other experiments you could try: sync the repo
> onto a local disk and see if the problem persists. Make sure you can
> access /afs/project/db/__db.001 with non-svn tools. Etc. etc.
You're aware that BDB on a networked filesystem is EXTREMELY
DANGEROUS? Right? From the filenames, I conclude you're using BDB and
from the path I conclude - like Tyler - that it's a networked file
system.
It's an unsupported and very much explicitly dangerous setup. I'm
sorry, but you have to quit using this setup if you like your
software. BTW: with FSFS, networked setups *are* supported, but *only*
if the network FS supports locks; meaning that - as far as I'm
informed - AFS is not an option. NFS only works for some well-written
v3 implementations.
Bye,
Erik.
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Received on 2009-01-27 21:36:42 CET