Bitrix. Which caching option to choose?

Question

1C-Bitrix

Hello!
There is a server with 64Gb of RAM and a medium-sized online store on 1C-Bitrix Small Business is running on it. With a site size of ~2 gigabytes (CMS and uploaded files), it also generates a file cache of about 20 gigabytes in size.
The official doc speaks of at least three options for placing this cache: in files, in memcached and in APC.
Now the cache is on the files. And so the question interests - how it is better to arrive with a cache?
My options:
1) Mount directories in tmpfs and make symlinks to them, thereby storing the file cache in RAM
2) Configure memcached (does it behave normally with 20GB of cache)?
3) Use APC for these purposes (did not find detailed docks)

Answer 1

Oddly enough, the file cache is more beneficial in your case. Due to caching on the side of the file system, the requested files will be read not from the disk, but from this cache, i.e. from memory, as in the case of memcached.
In order for this to work, the system needs to leave free memory that it could use for caching needs. Also, if you distribute large files somewhere, you need to do it through directio so that they do not flush your file cache.
The cache in memcached will not be more efficient - there will be no more memory, and you still have to cut its allocation somewhere in order to give it to memcached, and at the same time it will not be swapped, which is almost equivalent to allocating free memory for the file system cache.
The cache in memcached is needed for distributed processing of scripts on several backend servers when accessing the shared cache goes over the network. Also, it is needed if you have a separate server with a lot of memory that you decide to use for cache.

Answer 2

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