RE: io thread very slow copying binlogs
- Date: Fri, 20 Jan 2017 10:19:57 -0500
- From: "Morgan Tocker" <morgan.tocker@xxxxxxxxxx>
- Subject: RE: io thread very slow copying binlogs
> MySQL community edition 5.6.29, running Linux.
> Binlogs never seem to get caught up on slaves.
> I've done all I can, to validate that this isn't network or disk related.
> Disk tests (using iostat and other methods) show lots of bandwidth left on
> the slave and master.
> Network tests, such as:
> - using scp to copy binlogs directly
> - using different NICs to copy binlogs
> - using mysqlbinlog to snag logs (the most 'real' way I can think to
> simulate the replication thread copying binlogs from the master)
> All seem to show that network speed is blazingly fast.
> Yet, MySQL is barely getting 4mbit/sec across the network, and onto the
> And that's on a good day.
> Any immediate suggestions here? This seems very weird, and SQL thread is
> constantly running out of stuff to process.
Networking is not my strong-suit, but I have a suggestion:
Try lowering slave-net-timeout
I remember that we lowered the default in MySQL 5.7 (from 1hr to 60 seconds)
so that the connection between master/slave would be considered broken
faster. If you have the throughput on a graph it might better explain if it
is a constant 4mbit/sec or more broken.
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