Giving up on x buffers - losing files
Jon Noack
noackjr at alumni.rice.edu
Sun Jun 27 11:17:32 PDT 2004
On 06/26/04 23:38, Don Lewis wrote:
> On 26 Jun, Arjan van Leeuwen wrote:
>> Sometimes, particularly after doing a lot of file writes (i.e.
>> compiling a lot of ports, building world and mergemastering, etc),
>> I get the 'Giving up on x buffers' message on shutdown, and my
>> filesystems come up dirty when I restart.
>>
>> <snip>
>>
>> So, why does this happen? And how do I prevent it from happening?
>> This definitely does _not_ sound like something I want my servers
>> to do when 5.x goes -STABLE.
>
> I've mentioned this a couple of times on this list in the last six
> months or so. The last time was in the last couple of weeks. I can
> reliably trigger this problem with mergemaster.
>
> I'm pretty sure that the problem relates to soft updates and how the
> file system syncer is shut down, which leaves unresolved dependencies
> that keep a number of dirty blocks from being flushed to disk at the
> end of the system shutdown.
>
> I have some ideas on how to fix the problem, but I haven't had the
> time to work on it and nobody else has stepped up with a fix.
>
> I am able to reliably work around the problem by running the sync
> command and waiting a short while after running mergemaster and
> before shutting down or rebooting the machine.
If you're running X be sure to end your session instead of restarting
directly. I usually end the session, switch to a console, manually sync
as Don described, wait 30 seconds, manually sync again (just to be
sure), and then shutdown. Actually, I wrote a script to do it (sync;
sleep 30; sync; shutdown -r now).
I only had the problem a couple times, but never since starting to
manually sync.
On a more humorous note, trying to save time by restarting both your NFS
server and client workstation at the same time is a really bad idea,
especially when your home directory is NFS mounted... ;-)
Jon
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