Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:65922
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain lerdorf.com from 209.85.210.51 cause and error)
Message-ID: <5122E451.1040308@lerdorf.com>
Date: Mon, 18 Feb 2013 18:32:49 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2
MIME-Version: 1.0
To: Stas Malyshev <smalyshev@sugarcrm.com>
CC: "internals@lists.php.net" <internals@lists.php.net>
References: <CAHHbRnEUVcGqH6+++CWXM6XWobJn5MzKxLdfX9RHxoJ0uXaZdg@mail.gmail.com> <51229088.90306@lerdorf.com> <5122DA51.6090606@sugarcrm.com> <5122DBA9.2010004@lerdorf.com> <5122E00F.80409@sugarcrm.com>
In-Reply-To: <5122E00F.80409@sugarcrm.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] PHP causing high number of NFS getattr operations?
From: rasmus@lerdorf.com (Rasmus Lerdorf)

On 02/18/2013 06:14 PM, Stas Malyshev wrote:
> Hi!
> 
>> Yeah, but NFS, especially without the realpath cache, which you lose if
>> you turn on open_basedir, is deathly slow because of all the stats.
>>
>> Typically PHP scripts are not actually "writable files" and the way to
>> keep them in synch across multiple machines is to use a deploy
>> mechanism/rsynch to deploy them. You may very well have some writable
> 
> rsync may be way too slow if you need the change appear more or less
> "immediately" on all servers. Unless you run rsync each second if which
> case you're probably better off with NFS :)
> 
>> files that need to be shared at the app-level, but then we wouldn't be
>> talking about PHP stat calls and the realpath cache. And most people
> 
> You would still if the data is stored as php file. Which last time I
> tested - given APC or something like - was the fastest way to get a
> bunch of data into PHP (it was faster than loading and unserializing,
> even with APC/memcache).
> 
>> have moved to something like memcache for sharing writable data across
>> machines.
> 
> memcache is non-persistent. It's a cache, not a storage solution, so you
> can not use it for anything that actually needs to be stored permanently.

Sure, but then you can go with something like Redis.

But, again, if you go back to the original question, this has nothing to
do with often-changing data in a couple of PHP include files:

  We have several Apache 2.2 / PHP 5.4 / APC 3.1.13 servers all serving
  mostly PHP over NFS (we have separate servers for static content)."

So they are serving up all their PHP over NFS for some reason.

-Rasmus