Some questions about ctdb availability when some node is crashed

[XW Huang]

Dear Sahlberg,

I have checked ctdb getdbmap. It shows that test.tdb is persistent.
Thanks for your reply.

Sincerely,
Az


2012/11/18 ronnie sahlberg <ronniesahlberg at gmail.com>

> Is it really a persistent database you are using ?
>
> What does   'ctdb getdbmap' show ?
>
>
>
> On Sat, Nov 17, 2012 at 8:50 PM, Christopher R. Hertel <crh at samba.org>
> wrote:
> > Az,
> >
> > The command you are executing is:
> >
> >   ctdb pstore test.tdb /tmp/test /tmp/test
> >
> > So are you using the file pathname ("/tmp/test") as the key?  I think
> that
> > makes sense, but it is a little confusing to read.
> >
> > I find it interesting that the pstore subcommand is not listed in the man
> > page for ctdb.  It was added in 2010, I believe.
> >
> > Chris -)-----
> >
> > On 11/16/2012 10:02 AM, XW Huang wrote:
> >> Dear martin,
> >>
> >> Thanks for your reply!
> >>
> >> In my tests, the IPs hosted by the failed node was moved to other nodes
> >> correctly.
> >> But all records in test.tdb can not be fetched on all nodes, i.e.
> {node-0,
> >> node-1, node-2, node-3}.
> >> It seems hanging when doing ctdb_fetch_lock:force_migration
> >> when node-0, node-2, node-3 tries to fetch the record from test.tdb.
> >> Is there any mechanism to revoke __transaction_lock__?
> >>
> >> Thanks again. I really appreciate receiving any input from smart people
> >> like you guys.
> >>
> >> az
> >>
> >> 2012/11/16 Martin Schwenke <martin at meltin.net>
> >>
> >>> On Sun, 11 Nov 2012 15:23:02 +0800, XW Huang <xwhuang123 at gmail.com>
> >>> wrote:
> >>>
> >>>> A record (/tmp/test) is stored in a persistent tdb (test.tdb) by this
> >>>> command.
> >>>>
> >>>> $sudo ctdb pstore test.tdb /tmp/test /tmp/test
> >>>>
> >>>> This record is fetched again and again on node-1.
> >>>> Then, node-1's network interface was turned down to simulate it is
> >>> crashed
> >>>> by this command.
> >>>>
> >>>> $sudo ifconfig eth0 down
> >>>> [...]
> >>>
> >>>> [...]
> >>>> However, the records in test.tdb can not be fetched anymore.
> >>>> But "ctdb getdbstatus" says test.tdb is healthy
> >>>> and "ctdb catdb" can dump its content:
> >>>> [...]
> >>>
> >>> It sounds like you are still trying to fetch the record on node 1.
> >>> That won't work.  CTDB isn't available on that node.
> >>>
> >>> If you are providing a CIFS service using Samba/CTDB then when a node
> >>> fails, the IPs hosted by the failed node will be moved to other nodes
> >>> so that they can continue to provide the CIFS service. Then any data
> >>> that Samba needs from CTDB can be fetched on those other nodes.
> >>>
> >>> Does that help?  :-)
> >>>
> >>> peace & happiness,
> >>> martin
> >>>
> >
> > --
> > "Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
> > Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
> > jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development,
> uninq.
> > ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
> > OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org
>