rc7 is out! We’ve upgraded to Varnish 3.0.2, fixed bugs, and made improvements to make your cPanel WHM server run even more faster than litespeed! Head out to the varnish download page: http://www.unixy.net/varnish

In brief:

• Upgrade Varnish to 3.0.2
• Increase httpd hdr len for req/resp
• Increase session WS
• Add Varnish monitoring crontab job

rc8 will see two neat features. The first will is a Slashdot Survive URL opt-in list where if you were to receive enormous traffic, Varnish can shield your server by responding directly to those requests (completely bypassing Apache or any server-side processing). So serving a slashdot-like audience will require a small fixed amount of memory as opposed to an unpredictable amount of resources (and most likely a server crash). The second feature will deal with aggressive bots. This addition creates a shared memory store for bots so they sources pages from the same store and prevent server crashes due to aggressive bots.

There’s more in 1.4.5rc8 so stay tuned!

Enjoy!

We haven’t seen anyone explain the meaning of following Varnish error message found in the logs of your server in detail. So here it is for the curious:

Dec  5 12:31:31 server varnishd[28446]: Child (28447) not responding to CLI, killing it.
Dec  5 12:31:59 server varnishd[28446]: Child (28447) died signal=3
Dec  5 12:32:03 server varnishd[28446]: child (22431) Started
Dec  5 12:32:04 server varnishd[28446]: Child (22431) said Child starts
Dec  5 12:32:04 server varnishd[28446]: Child (22431) said SMF.s0 mmap'ed 268435456 bytes of 268435456

The message above comes from the Varnish Manager. The Manager is the Varnish process (there are two Varnish processes) that monitors and manages the Varnish caching process. Here it’s telling us that caching process has stopped responding back with a PONG to its PING. A ping from the Manager to the Cache process with its response look like this and happens every 3 seconds (at least in this configuration):

    0 CLI          - Rd ping
    0 CLI          - Wr 200 19 PONG 1323181633 1.0
    0 CLI          - Rd ping
    0 CLI          - Wr 200 19 PONG 1323181636 1.0

So going back to the error message, the Manager is telling us that it hasn’t received a “PONG” back from the Cache process in a while. A “while” is controlled by the variable cli_timeout which has a default of 10 seconds in Varnish 3.x and 20 seconds in Varnish 2.x. So the Manager waits for about 10 seconds before it fires a UNIX kill using signal SIGQUIT (signal=3). Next the Manager starts the child back up again afresh.

You may be asking yourself: why is the Cache process not responding? There are a few of possible causes. Either the cache process is deadlocked (deep code issue) or the server is under a very heavy disk IO load / memory shortage. So how do you determine which category you fall under? I recommend checking the load average and memory utilization levels on your server using Sysstat tools.

Did you know?

UNIXy is a fully managed server and cluster provider. What this means is we don’t expect you to know anything about servers or server management. The good news is it doesn’t cost you extra to have us manage your UNIXy server! Get in touch with us here to get the ball rolling!

 

That’s all folks.

Varnish PHP bindings are useful for folks that need to manage Varnish from PHP. A palpable version of the extension code has finally been released. Keep in mind that the release is early beta. Nonetheless, the milestone is significant. So, what can one accomplish with the API?

Here’s a list of the most important function calls:

 stop
 start
 banUrl - Purge URL
 ban - Free form purge command
 isRunning - Boolean
 setPort - Set the admin port
 getSnapshot - Retrieve statistics snapshots
 getLine - Retrieve log entry

We are keeping a close eye on the development of the PHP Varnish extension and will update this page.

About UNIXY

UNIXY is a long-time Varnish Cache user and evangelist. They have been offering Varnish acceleration to their VPS, dedicated server, and cluster clients for more than three years. They have released the first cPanel Varnish plugin as well as spun a new startup,Fastlayer, the on-demand HTTP accelerator for the cloud.

That’s all folks!

Varnish, the state-of-the-art HTTP accelerator, v3.0 (up from v2.1.x) is scheduled to be released in a few hours. The folks at Varnish Cache have worked tirelessly to get the 3.0 release out of the door. Congratulations on work well done!

Here are some of the major changes and additions:

Plugin Support – VMOD

VMOD is to Varnish as loadable module is to a kernel.  The new Varnish provides a programmable interface that enables expanding the VCL (Varnish Configuration Language). This VMOD feature includes relatively advanced concepts like functions, pointers, and data types. I think this is the most complex piece to go in v3.0.

Streaming Support

This is a long awaited feature. Up until today, Varnish broke HTTP streaming slowing down adoption of the software in the multimedia space and content delivery. This feature makes it possible to accelerate HTTP streaming. Streaming is controlled via the boolean beresp.do_stream.

Compression and Decompression Support – ESI Twist

Having Varnish do compression and decompression adds flexibility and performance in one shot. The compression level is controllable via the variable gzip_level. With this feature, you can now compress what is not compressed should there be a legacy issue; Decompress on the fly for ESI and compress; Modify the compression level; Offload compression to a host of machines. And the list goes on…

Improved Documentation

The new Varnish boasts improved documentation that is “in much better shape than before.” This is excellent news because,  in my opinion, this used to be THE pain point.

About UNIXY

UNIXY is a long-time Varnish Cache user and evangelist. They have been offering Varnish acceleration to their clients for more than three years. They have released the first cPanel Varnish plugin as well as spun a new startup, Fastlayer, the on-demand HTTP accelerator for the cloud.

That’s all folks!

We’ve had very positive results accelerating XenForo with Varnish (in a cluster configuration). In terms of VCL, we’ve taken a slightly different approach but it results in better caching / acceleration. We’ve allocated a small per-user cache (logged in users), which makes XenForo pages load even faster than normal conditions. This reserved cache is rather transparent to the end user so no code changes are required. In fact, the acceleration we provide requires no modification to any XF files at all.

Static files, however, are stripped out of cookies in the Varnish VCL and served from the same cache area. The performance gains are tremendous. We’ve already published a Varnish plugin for cPanel and DirectAdmin that incorporates these tweaks. Feel free to read more about it here: http://www.unixy.net/varnish

Cheers

Everyone knows that PHP opcode caching, or any kind of PHP caching for that matter, is not possible with suPHP. This is a trade off of choosing security over performance. The performance hit of running scripts under suPHP is, however, significant. It’s so significant that pages take noticeably longer to display at the browser. Also, the server load goes through the roof during traffic spikes.

The workaround we’re presenting in this post doesn’t require any compromise in terms of security. You get to keep suPHP with its security blanket but also get a tremendous performance boost from caching. The caching in question comes from Varnish Cache, the open source HTTP accelerator that runs in front Apache (or any other Web server for that matter). We’ve developed a Varnish cPanel script or plugin that allows anyone to run Varnish. The script installs, configures, manages, and integrates Varnish with cPanel without you needing to do any maintenance from the terminal.

Varnish Cache is so powerful that the performance gains surpass that of PHP opcode caching! Both internal and independent benchmarks have shown that our cPanel Varnish Plugin (and VCL) performs better than the fastest Web server in the market including Nginx, Litespeed, and Lighttpd. Read more on the results.

The following video shows how one can easily install the Varnish cPanel script:

Here’s some feedback from people that are using the script: http://www.unixy.net/secure/knowledgebase.php?action=displayarticle&id=25

That’s all folks!