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I am trying to import a database into a slave server. The process is being slowed because mysql calls fsync at a crazy rate. The jbd2/dm-0-8 runs at 80 - 99 % continuously but the throughput is quite low. It was running at a few kb/s till I implemented the following changes

innodb_flush_sync = OFF
sync_binlog= 0
sync_frm = ON
sync_master_info = 0
sync_relay_log = 10000
sync_relay_log_info = 0
innodb_flush_log_at_trx_commit = 0

It's now running at about 12Mb/s. I'm sure if I can do something further to decrease fsync calls it will help this.

Any suggestions?

  • innodb_doublewrite = 0 and innodb_flush_log_at_trx_commit = 0 depending on your MySQL version, too, but I wonder if the folks at Database Administrators might have more knowledge than us... – derobert Feb 7 '17 at 21:10
  • Thanks. I'll give that a try, on both fronts. I didn't see the Database Administrators forum. – Wayne Feb 8 '17 at 11:29
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    I'm voting to close this question as off-topic because it's for dba.stackexchange.com – poige Mar 3 '18 at 10:23
  • 1
    Configuring software that runs on Unix is on-topic here. They may get better answers at DBA (or may not), but I'm voting to leave open here. – Jeff Schaller Mar 3 '18 at 13:21

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