maria-discuss team mailing list archive

[Jeff Dyke <jeff.dyke@xxxxxxxxx>]

Yes percona toolkit is great.  But executing a lot of those tools on a
large dataset can take time.  If you have spent the time to put up "a
couple of slaves".  Those can be transitioned into being a galera cluster.
The way i use the cluster, is to route all traffic through HAProxy(there
are other ways, like ProxySQL), with one live read/write and two being
members that actually replicate down to slaves.  The reason i route it
through HAProxy is it will auto failover and you since writes to the target
database are locked pessimistically, writes to the other members use
opportunistic lock, which a simple bash script on multiple servers that
reads and writes from the same table, can cause a deadlock.  Same issue
impacts RDS clusters.

Sorry for the long winded answer, but I wanted to show how a member of a
cluster doesn't have to deal with lags of its members, and some of the
risks. Nodes run with the same GTID and alert if they are different.  I had
a similar set up for many jobs and if galera was as mature as it is now
built with mariadb, i would have used it in the same way.  The non
read/write nodes can also be backup safe as you can desync them and resync
them during logical or physical backups.

I wanted to offer an alternate solution based on my perceptions of your
server setup.

All the best

On Fri, Jul 24, 2020 at 6:55 AM Vincent Hoffman-Kazlauskas <
vince@xxxxxxxxxxxx> wrote:

> I'd have a look at the percona toolkit
> https://www.percona.com/software/database-tools/percona-toolkit. Its
> free and got loads and loads of useful stuff but for this in particular
> have a look at
> https://www.percona.com/doc/percona-toolkit/LATEST/pt-table-checksum.html
>
> Vince
>
> On 23/07/2020 19:53, Richard Reina wrote:
> > Good afternoon,
> >
> > I have a couple slaves that I have set up over the last year. Is there a
> > way to perhaps compare them to the master on a database or table level
> > to ensure their integrity?
> >
> > Thanks
> >
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