How to increase memcache slab size above 1MB with dalli and Rails?

Question

I'm using Ruby on Rails and dalli gem to do caching with memcache.

The default value (value as in key-value store, aka slab) max size is 1MB.

I would like to increase this to 2MB.

The documentation of dalli says:

value_max_bytes: The maximum size of a value in memcached. Defaults to 1MB, this can be increased with memcached's -I parameter. You must also configure Dalli to allow the larger size here.

With the -I option of memcached, how do I specify 2MB? Is it -I2 or -I2000? (the documentation isn't clear on this)

For the dalli gem, I have, in environments/development.rb

config.cache_store = :dalli_store

I don't have explicit mention of Dalli::Client.new So how can I set the value_max_bytes?

I've looked at the related question on stackoverflow, it seems that I need to install the rack-cache gem. Is this necessary?

Thank you.

Answer 1

Start the memcached with the command:

memcached -p 11211 -I2m

In Rails environment file, eg config/environments/production.rb, use the following syntax:

config.cache_store = :dalli_store, { value_max_bytes: 2000000 }