Dreampress and XCache


#1

I’ve had good success keeping CPU and memory usage down with decent load times with my Dreampress hosting site through Varnish, some .htaccess expires, Pagespeed, and the Memcached object drop-in for Wordpress.

I’d like to get back to using W3TC for an upcoming event that will result in high load. On shared hosting previously I found W3TC using disk caching to be worse than useful. I’ve XCache checked off now with Dreampress. When I try to use Opcode: Xcache in W3TC, I receive an error.

Any tips to getting XCache up and running on Dreampress? Is XCache object caching going to be superior to Memcached?

Thanks!


#2

You can’t install Xcache on DreamPress. It’s not supported. We feel MemcacheD is a better mesh for Varnish and DP.


#3

According to the Dreamhost control panel for Dreampress configured domains, “Support PHP XCache” is enabled by default. What do you mean that it is not supported?

Xcache and Memcache caching two different things. Xcache uses pre-compiled php code in memory so that it does not need to fork a new process to re-run the php.

Memcache is a distributed memory caching system, it does not improve the performance of PHP since it stores data only.


#4

From another thread: “It’s running, just not in a way that W3TC likes :confused: Memcached, IMO, is better.”

XCache would make a lot of sense for my Woocommerce site with its precompiling. And Tearstone is right, it is enabled in the web panel. But as Ipstenu suggested, something about the install doesn’t work with W3TC (or the XCache Wordpress object drop-in either FYI. When I installed that, it spawned many stalled php5 processes and swamped the server.)


#5

Dizziness, the Xcache drop down does not work on W3TC.


#6

So, if its not useable, why is it enabled by default in Dreampress? https://www.dropbox.com/s/tny0mh5wyf1imoj/Screenshot%202014-02-19%2015.32.08.png


#7

Well we also don’t support you using W3TC in DreamPress so … there’s that too :slight_smile:


#8

I appologize for the bump of this thread, but I have to agree with dizziness. If it’s not ‘supported’ then why is it default and optional within the dreamhost PS option menu?

Ipstenu-DH… Your replies are not informative what so ever. Lack of details and misinformation regarding xcache. I’d assume you are a DH staff member, so it would be nice if you’d be detailed about it rather giving ‘half’ information in your replies. It’s not helping anyone. If it’s not supported, give details why. And why is it enabled by default / optional then in the Dreamhost control panel?


#9

The answer is weird and confusing, so I’ll try to explain.

First, I misspoke that it’s not installed. XCache IS installed, however it’s not really set up to be the OpCache that W3TC wants. On the server xcahce IS supported, however the way W3TC works with xcache does not work well (if at all) with our implementation. So when someone says “When I try to use Opcode: Xcache in W3TC, I receive an error.” the answer there is “Yes, we know, it doesn’t work the way W3TC wants it to.” So what I shold have said, and again, my bad, is that “Xcache is not compatible with W3TC, and not supported for use with it.”

But that’s not really the heart of the question. See, we have MemcacheD on the servers for dreamPress, which we DO feel is a better mesh, and while you certainly can activate xcache with DreamPress, it won’t harm anything, but it also won’t magically work with W3TC, which again, we don’t support on DreamPress right now.

The opcode caching we built in to DreamPress is evident in the file object-cache.php found in your wp-content folder, and that was built to use MemcacheD. If you wanted to use W3TC you’d have to remove that and THEN tell W3TC to use Memcached for OpCode caching, not Xcache.

Which at this point is all theory. I haven’t tried to use W3TC on DreamPress in depth since we don’t support it and I put more of my time into the Varnish plugin that I maintain the code for.