

Database Migrations - Lessons from Failure, and Tips for success - mbseid
http://mbseid.com/database-migrations-lessons-from-failure/

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politician
> After every write to our database, we had to wait for the disk to catch up.

After all of the guffaw we just went through with MongoDB, is disabling fsync
the right solution to speeding up MySQL migrations?

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mbseid
Nope, it probably isn't best for performance. It wasn't my call to make, and
it has been operating like that for years.

But for data stability, I see why it was done. It is a trade off, one that we
may reconsider down the line.

Edit: Misread the question. I'm not exactly sure, but it significantly
improves speed, enough for us to complete the migration, then switch it back
on during production.

One note: when running on a VM, it seems not to flush to disk regardless of
the OS setting. Probably because of the virtualization software

