VPS optimized cpanel - what is the catch?

[weetabix]

http://blog.cpanel.net/?p=37

sooo... there must be some kind of tradeoff... doesn't it?

[TheHeartSmasher]

Haha, you could be right.
Maybe they are just prepping all Cpanel builds for their own superior VPS systems that you could install on a regular server that will enable hosting companies to use Cpanel VPS .

[dan223]

I got there email regarding this, first thing I thought is if this can be optimzed on VPS's why not on dedicated servers as well?

[WebJIVE]

If your on a VPS currently and want to migrate to VPS optimized, is that option available and what do you give up (trade offs)?

The blog entry was ver LIGHT on specifics.

[dan223]

As stated in the blog, you don't loose any features, and its currently in the edge build and will automatically change when you update to that build.

[nyjimbo]

I got there email regarding this, first thing I thought is if this can be optimzed on VPS's why not on dedicated servers as well?

I'm sure there are tradeoffs, probably in performance. Let's face it, the VPS is the poor-mans server. Probably going to be lots more disk i/o rather than keeping things in memory.

"The reduction in memory usage for each install allows web hosts the ability to host more domains per virtual machine." probably translates to more clients per VPS so you dont need to go to a dedicated machine as quickly which is cheaper for the web host/reseller. So those $19.95 a month VPS accounts will become the standard for new "web hosting companies".

"This increase enables hosts to provide a more efficient and eco-friendly server base with fewer physical machines." , wow I never thought I would see that.

[wizzy420]

This is what I want to know:

• What are the negatives?
• If it's so great, why not distribute the changed to ALL versions instead of just VPS versions?
• Where is memory saved and what might the side effects be?

It concerns me that they're talking about all the memory reduction, while at the same time saying "don't worry, everything will stay exactly the same!" which can't be true. It sounds like we're talking about some serious changes and tweaks -- something this major needs to be addressed in more detail.

What is being hidden from us ??

[jpetersen]

Below is everything I've found so far that relates to the memory improvements
made by cPanel on VDS servers. Much of this was found on changelog.cpanel.net,
which has an RSS feed for keeping you updated when newer versions of cPanel,
easyapache, or the cPanel installer are released.

This is from a test VDS, currently using 11.22.0-EDGE_23043 on CentOS release 4.6:

# ls -l /var/cpanel/vps_optimized/
total 0
-rw-r--r--  1 root root 0 Mar 25 17:01 1.0
-rw-r--r--  1 root root 0 Apr  2 13:24 1.3
-rw-r--r--  1 root root 0 Apr  4 13:42 1.7

Note time timestamp of March 25th for v1.0. That date coincides with these notes
at changelog.cpanel.net for EDGE:

Edge 22346
2008-03-25 13:09:14

Added cpanel/bin/low_mem_mods to install memory-optimized cPanel Perl modules

Improved overall memory consumption by switching to memory-optimized modules and removing the POSIX module

Note the reference to "cpanel/bin/low_mem_mods". Let's take a peek:

# file /usr/local/cpanel/bin/low_mem_mods
/usr/local/cpanel/bin/low_mem_mods: perl script text executable

Viewing the file you'll see what appears to be some new cPanel modules
which you can find here:

/usr/local/cpanel/src/Cpanel-POSIX-Tiny-0.6/
/usr/local/cpanel/src/Cpanel-Cleanup-0.4/
/usr/local/cpanel/src/Cpanel-FastMath-0.2/

This is pretty self explanatory:

Edge 22347
2008-03-27 13:35:20

Updated cpsrvd to remove usage of Whostmgr::ACLS for memory reduction.

This is covered at the cPanel blog:

Edge 23019
2008-04-04 06:59:25

Replaced eximstats, antirelayd and cpbandwd with new Tailwatch application

So, instead of having 3 separate, constantly running applications, there is now
1 lightweight (uses less resources, such as memory) application to handle the same tasks.


I don't know how much memory easyapache used to typically use in the past on
average, but a test I did earlier showed that a VDS idling on 71M of mem would use
up to 138M of mem when recompiling Apache 2.2.8, PHP 5.2.5 with Zend and
ionCube, as well as modsecurity 2.1.4 and 41 various PHP modules. The memory
usage of the VDS was checked every second, and only twice did it peak at 138M.
Most of the time it was around 110M or so. This is likely an improvement over
past runs of easyapache3 due to this:

Easyapache 3999
2008-03-18 12:13:48

Limit gcc memory usage on VPS systems by increasing frequency of garbage collection

Garbage collection basically means freeing up memory by applications that no longer
need it. A good explanation I found on reddit recently that everyone can understand is here.


Tradeoffs? I see no so far, although someone did post on webhostingtalk.com about
seeing higher CPU utilization with no user activity taking place. However, that means
little without any detail having been provided, in my opinion (where was the CPU
utilization taking place? What processes were running at the time? Were backups
being run? Was MySQL completely idle? etc). My test VDS idles at 0.00 with 0% CPU
utilization, and it sits on a node with other servers, most, if not all of which are using cPanel.

Reasons why the optimizations haven't been pushed to non VDS servers? I speculate that
this is because coding is a process of careful planning, development, and testing. Non
critical updates don't typically get pushed out in a rushed manner to every product
you have. Doing so can be disastrous. That's why cPanel has the different trees: EDGE,
RELEASE, CURRENT, etc. New features are usually added to EDGE first, then they work
their way down to the other trees over time when proven to be stable enough to do so.

If you're concerned when cPanel implements new features, I would recommend using STABLE
and waiting to see what others have to say when they've test driven any new changes,
then updating. This isn't a major overhaul of cPanel by any means from what I've seen,
but an improved way of doing tasks that were already part of the software (and without the
expense of crippling or removing any features that were already there and necessary for
using it).

That's my $0.02. Kudos to cPanel for the improvements where they currently matter most.

[rich_505]

I've seen 10-20% lower RAM usage during idle state, and CPU usage is now hovering around 10-20% when idle with it rarely peaking about 80% whereas in the past I've seen peaks of 100-200%. VPS Optimized has pretty much transformed my VPS from a VPS that needs upgrading to a Dedicated Server into a much more stable and reliable/responsive system.

Only problems I've noticed:

'Theme Changer' in cPanel doesn't seem to work for clients, this can be done via WHM fine.
RVSkins doesn't appear to be working, again can be done via WHM without issue.

[dan223]

This is in edge, therefore you can't expect it to be bug free. But I am still wondering why this can't be done for dedicated servers if there are no tradeoffs.

[rich_505]

Did I say I had a problem with these minor bugs?

[rpmws]

I got there email regarding this, first thing I thought is if this can be optimzed on VPS's why not on dedicated servers as well?

you will see improvements also on regular servers. the tailwatchd for one and some other things. VPS installs are going to see the biggest difference because they are limited on resources in the first place. Don't expect to see a huge difference in a box with 16GB of ram. But on a old server with 256MB it gonna help

[wizzy420]

you will see improvements also on regular servers. the tailwatchd for one and some other things. VPS installs are going to see the biggest difference because they are limited on resources in the first place. Don't expect to see a huge difference in a box with 16GB of ram. But on a old server with 256MB it gonna help

I would imagine a lot of people with a smaller number of hosts have boxes (dedicated) with 1GB -2GB of RAM

In these cases having an extra 100-200MB would still be a help. That's like an extra 10% for system buffers.

[rpmws]

I would imagine a lot of people with a smaller number of hosts have boxes (dedicated) with 1GB -2GB of RAM

In these cases having an extra 100-200MB would still be a help. That's like an extra 10% for system buffers.

I manage a coule of 512MB boxes that have a couple hundred accounts on them ..so yes I agree and I think it's great these improvements are needed and appreachated very much. I look forward to everyone gaining benifits from it.

[dbstephens]

Well I bumped my personal VPS to EDGE to give the VPS optimized a try...

The catch is that now all of your cPanels and WHM windows have a cPanel or WHM VPS Optimized logo on them.

Bad if you are selling hosting from a VPS

If you use a custom skin then you are fine.