I know this is not the place for this, but downed NFS connections ("dead" ones)
can take anything
on server down with it, just consuming resources retrying connection.
Just read server load average to get the picture.
You'll be lucky if you manage to kill "dead" nfs processes .
Regards .
Pablo Sánchez
On 01/17/2017 12:24 PM, Dirk Hagedorn (JIRA) wrote:
> Connections fail due to dead NFS mount points
> ---------------------------------------------
>
> Key: CORE-5458
> URL: http://tracker.firebirdsql.org/browse/CORE-5458
> Project: Firebird Core
> Issue Type: Bug
> Affects Versions: 2.5.2
> Environment: Ubuntu 14.04.5 LTS, Firebird/linux AMD64 (access
> method), version "LI-V2.5.2.26540 Firebird 2.5"
> Reporter: Dirk Hagedorn
>
>
> Short summary:
>
> - Ubuntu Server runs Firebird 2.5.2 and has mounted two NAS via NFS
> - both NAS have nothing to do with Firebird (no database related files on it)
> - if a NAS doesn't respond anymore (shut down, cable unplugged) but NFS share
> still mounted -> connection to Firebird possible anymore
> - existing connections to Firebird keep working, new connections aren't
> possible (no timeout, waits endlessly)
>
> Some more words:
>
> I have an Ubuntu server 14.04.5 LTS running Firebird 2.5.2 for some Windows
> clients and local applications (running directly on the server) using isql-fb
> or Perl::DBI. The attached NAS are mounted via NFS for backups. The NAS has
> nothing to do with Firebird: No databases are stored on it, no configurations
> files, no symbolic links are
>
> I had to shut down one of the NAS and forgot to unmount its NFS share before.
> I got some angry calls from the Windows users that "the tools don't work
> anymore". "Hu? I shut down the NAS and the database applications won't work
> anymore? WTF!?"
>
> It turned out that no Firebird client was able to connect anymore, either the
> local "isql-db" directly on the server or by ODBC-Client or by gds32.dll.
> Nothing worked anymore, no warning, no timeout, the clients just waited
> endlessly for a connection wich couldn't be established. Existing database
> connections kept on working (sure, why shouldn't they, I just shut down a
> NAS?)
>
> I can reproduce this phenomenon:
>
> Scenario #1:
> - keep NAS mounted via NFS, unplug its network cable = "dead" NFS mount -> no
> Firebird connection possible / clients wait endlessly
> - plug in network cable -> still waiting Firebird clients connect immediately
>
> Scenario #2:
> - unmount NAS before unplugging its network cable -> normal Firebird
> behaviour = connections possible
>
> Again: the database files are NOT stored on the NAS. Firebird does NOT have
> to access the NAS for any purposes. But it hangs if the NFS mount is dead.
>
> I haven't checked if it's NFS specific or if Firebird will even file with
> dead (let's say) Samba mounts or anything else.
>
> Connection method: The tools connect via "hostname:aliasname". I tried to
> connect via isql-fb directly on the server with "isql-fb
> /absolut/path/database.fdb -user bar -password bar", it didn't work either.
>
>
> ISQL Version: LI-V2.5.2.26540 Firebird 2.5
> Server version:
> Firebird/linux AMD64 (access method), version "LI-V2.5.2.26540 Firebird 2.5"
> Firebird/linux AMD64 (remote server), version "LI-V2.5.2.26540 Firebird
> 2.5/tcp (neo)/P12"
> Firebird/linux AMD64 (remote interface), version "LI-V2.5.2.26540 Firebird
> 2.5/tcp (neo)/P12"
> on disk structure version 11.2
>
>
> Sorry if this bug report doesn't fit your usual requirements. It's my first
> one and I even registered here to report this weird issue.
>
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