FlashCache and ditching caches.

I have to admit that FlashCache for Linux looks pretty cool.

It basically lets you use a block device SSD as cache.

Another hack is to mount the SSD as swap and tell InnoDB to use say 100GB of memory. I haven’t tested this but it might be a fun hack :)

We’ve actually migrated away from using SSD in production – at least for now.

The performance just wasn’t THAT great in our configuration. I’m still semi optimistic but not as much as I was a year ago.

I think if I were to do it again I would drop RAID everywhere with SSD and make sure my database layer can correctly route queries to the right MySQL instance.

Each SSD would need to be on its own database server with its own replication thread.

We’re also ditching use of caches and instead requiring that all of the applications memory reside in memory. It’s way cheaper on a per-IOP basis this way and just a lot easier to admin.


  1. todd

    Hey Kevin, I was wondering if you could explain what ” instead requiring that all of the applications memory reside in memory” means in a little more detail? It’s not clear what you’ve learned here.

    thanks






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