maria-discuss team mailing list archive

[Andrew Garner <muzazzi@xxxxxxxxx>]

What SST method are you using? Based on this I expect you are using rsync.

I imagine someone knows more detailed answers here, but from my understanding:

Internally the bin/wsrep_sst_rsync script indicates it needs "flush
tables" to the server and the server runs this "sst_flush_tables()"
function that effectively runs:

FLUSH TABLES WITH READ LOCK
+ reload_acl_and_cache(thd, REFRESH_ENGINE_LOG | REFRESH_BINARY_LOG, ...)

Which I think is equivalent to FLUSH ENGINE LOGS / FLUSH BINARY LOGS.
I think around this point it also sets innodb_disallow_writes to stop
InnoDB's background I/O (so rsync can be consistent).

At that point the bin/wsrep_sst_rsync script graps the last
$BINLOG_N_FILES binary logs, which I believe is hardcoded to '1' and
seems to be evaluated after this flush condition.   But internally I
guess InnoDB can have a prepared transaction related to a previous
binlog.

I've wrestled with similar problems writing backup recovery routines
for MariaDB + snapshot backups (typically via LVM snapshots), where I
typically have to go 2 logs back and it seems to eliminate this kind
of failure.  You might be able to bump up BINLOG_N_FILES in
/usr/bin/wsrep_sst_rsync (or wherever it is located) and see if that
resolves your race condition.

Alternatively I think percona-xtrabackup has solved this problem[1] a
while back as well, so a different wsrep-sst-method may be an option.
 Although xtrabackup has its own problems - in particularly I've found
that xtrabackup currently doesn't handle lost+found directories too
well[2], so you either have to avoid having the datadir directly under
the mountpoint or use some other filesystem (such as XFS) that doesn't
create lost+found.  I suppose if you're using encryption, xtrabackup
is also not currently an option. :)

~Andrew

[1] https://bugs.launchpad.net/percona-xtrabackup/+bug/1254227
[2] https://bugs.launchpad.net/percona-xtrabackup/+bug/1272329

On Wed, Apr 13, 2016 at 4:27 PM, Igor Mazur <igor.kozlov@xxxxxxxxx> wrote:
> Hi,
>
> Almost everytime when I join node to Galera cluster (MariaDB 10.1.13) I'm
> getting an error after SST:
>
> 2016-04-13 21:09:37 139932281419712 [Note] Recovering after a crash using
> /var/log/mysql/mariadb-bin
> 2016-04-13 21:09:37 139932281419712 [ERROR] Binlog file
> '/var/log/mysql/mariadb-bin.000023' not found in binlog index, needed for
> recovery. Aborting.
> 2016-04-13 21:09:37 139932281419712 [ERROR] Crash recovery failed. Either
> correct the problem (if it's, for example, out of memory error) and restart,
> or delete (or rename) binary log and start mysqld with
> --tc-heuristic-recover={commit|rollback}
> 2016-04-13 21:09:37 139932281419712 [ERROR] Can't init tc log
> 2016-04-13 21:09:37 139932281419712 [ERROR] Aborting
>
> As I see, almost every SST rotates a log file and downloads last (in example
> above I have mariadb-bin.000024), and not previous. But for recovering it
> needs previous.
> Sometimes I'm lucky and it restores.
>
> Anyone knows why it rotates a log and is it possible to force it to load
> more than last log file?
>
> Igor Mazur
>
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