VPS Mysql server

[RaZor Edge]

Hi,

I known that is it current practice for dedicated server owners to have different services (web, email, database) hosted on different servers. Other than load balancing, this seems to be a great way to reduce load when a server become too busy.

My question may seems funny... but is this kind of options also available for VPS?

I'm using vbulletin and it seems pretty easy to configure a mysql server outside the server where the forum is actually hosted.

Would that kind of solution slow down my forum or have other kind of bad effect?

Having a VPS to only host Mysql with nothing else (no need for cpanel or other intensive kind of programs, exept something like phpmyadmin and memcache I suppose) seems a pretty cheap way to buy more ressources for a website.

I do not need something like that right now, but if my website continue to expense... who knows! This seems a better sollution than buy a dedicated server...

Any help is welcome!

Thanks!

[thisisit3]

Yes its possible but make sure you ask them to host the extra VPS into different hardware nodes (but on the same data center). Thus, high cpu load on your web server (which can affect the entire hardware node) won't affect your database and you still have great network response between the two VPS nodes.

Just remember that a VPS has the equivalent cpu power of a Pentium 2... and about the same amount of memory

[Gwaihir]

Indeed that's done to spread load over more than one machine. But IMHO it also means that it isn't all that interesting until you are using and stressing one complete machine.

Isn't it just as cost effective to upgrade to the next higher VPS plan? Or, for a simple vbulletin site: what about SDX? It seems the provide to power of the larger VPSses for a very nice price. Another way to more power in a very cost effective way could be to pick up one of the bargain bin dedicated servers. You'd have to manager that yourself, but well, you sound like you're up to that .

[RaZor Edge]

Indeed that's done to spread load over more than one machine. But IMHO it also means that it isn't all that interesting until you are using and stressing one complete machine.

Isn't it just as cost effective to upgrade to the next higher VPS plan? Or, for a simple vbulletin site: what about SDX? It seems the provide to power of the larger VPSses for a very nice price. Another way to more power in a very cost effective way could be to pick up one of the bargain bin dedicated servers. You'd have to manager that yourself, but well, you sound like you're up to that .

Thanks for replying. It is much appreciated.

I'm already on a VPS Enterprise plan (the bigger one). I recently add 128mb more RAM to it.

I have follow with interest the many discussions here comparing VPS vs SDX. I understand that VPS is more for control, and SDX more for power. But i am very relunctant to transfer my website from my VPS (wich cost something like 70$/month) to a plan who cost +/-25$!

Dunno... but it just seems too good to be truth!

My VPS was perfectly running for a long time, but my website is growing more and more each day. Most of the time, server load is perfect (below 1.00) but at certain time of the day, things become more difficult (but not dramatical, for now).

I have disable pretty much anything I don't really need (spam assasin, log processing, and tweak almost everything in cpanel) and optimize mysql and apache (+ apc cache).

My RAM usage have drop radically! (there was also a misconfiguration in my burstable ram that have been fix now by support)

But now CPU seems to go high sometimes. It seems to really depend on what other VPS's on the node are using because some times at peak hour server can stay around 0.40... but other time go more like 3.00 or 4.00 with apache or mysql going down.

It seems related to apache because most of the time, my TOP is like this:

top - 20:51:47 up 5 days, 52 min,  1 user,  load average: 0.29, 0.28, 0.25
Tasks:  55 total,   1 running,  53 sleeping,   0 stopped,   1 zombie
Cpu(s):  1.0% us,  0.3% sy,  0.0% ni, 98.7% id,  0.0% wa,  0.0% hi,  0.0% si
Mem:   8301332k total,  7931868k used,   369464k free,    66620k buffers
Swap:  1020116k total,     4096k used,  1016020k free,  5028140k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                       
32145 nobody    16   0 89696  25m  19m S    1  0.3   0:06.69 httpd                                                                                         
 6040 nobody    15   0 89612  24m  18m S    1  0.3   0:05.46 httpd                                                                                         
26371 nobody    15   0 89412  20m  13m S    1  0.2   0:00.35 httpd                                                                                         
21971 root      16   0  1896 1040  788 R    0  0.0   0:01.32 top                                                                                           
28013 nobody    15   0 89680  25m  18m S    0  0.3   0:06.09 httpd                                                                                         
 9469 nobody    15   0 89632  25m  18m S    0  0.3   0:04.03 httpd                                                                                         
21917 nobody    15   0 89516  22m  16m S    0  0.3   0:00.98 httpd                                                                                         
26451 nobody    15   0 89528  19m  12m S    0  0.2   0:00.53 httpd                                                                                         
    1 root      15   0  1628  604  524 S    0  0.0   0:00.74 init                                                                                          
 7714 root      16   0  1532  528  440 S    0  0.0   0:00.52 syslogd                                                                                       
 7724 root      18   0  1456  376  320 S    0  0.0   0:00.00 courierlogger                                                                                 
 7725 root      16   0  1804  592  484 S    0  0.0   0:00.00 authdaemond                                                                                   
 7732 root      15   0  1804  364  244 S    0  0.0   0:00.02 authdaemond                                                                                   
 7733 root      15   0  1804  364  244 S    0  0.0   0:00.02 authdaemond                                                                                   
10196 named     21   0 68168 2968 1896 S    0  0.0   0:38.48 named                                                                                         
10215 root      16   0  4028 1140  844 S    0  0.0   0:00.55 sshd                                                                                          
10228 root      18   0  2152 1124  948 S    0  0.0   0:00.00 mysqld_safe                                                                                   
11289 mysql      5 -10  184m 152m 4220 S    0  1.9 130:31.98 mysqld                                                                                        
11320 root      15   0  1460  380  320 S    0  0.0   0:00.00 courierlogger                                                                                 
11321 root      16   0  1568  516  440 S    0  0.0   0:00.00 couriertcpd                                                                                   
11329 root      18   0  1460  312  260 S    0  0.0   0:00.00 courierlogger                                                                                 
11330 root      18   0  1568  488  412 S    0  0.0   0:00.00 couriertcpd                                                                                   
11336 root      16   0  1460  380  320 S    0  0.0   0:00.12 courierlogger                                                                                 
11337 root      16   0  1568  516  440 S    0  0.0   0:00.15 couriertcpd                                                                                   
11342 root      21   0  1460  312  260 S    0  0.0   0:00.00 courierlogger                                                                                 
11343 root      18   0  1568  488  412 S    0  0.0   0:00.00 couriertcpd                                                                                   
11411 mailnull  16   0  7496 2036 1624 S    0  0.0   0:01.33 exim                                                                                          
11418 mailnull  16   0  7492 2004 1604 S    0  0.0   0:00.01 exim                                                                                          
11493 root      19   0  3580  924  728 S    0  0.0   0:00.00 pure-authd                                                                                    
11512 root      16   0  2484  916  524 S    0  0.0   0:00.60 crond

When problems happens, the number of task go from +/- 50 to +/- 150 or 180. It can happen 2 or 3 times a day. Since I have lower my RAM usage, I have obviously less problems. But it still happens...

I was thinking that a slow query or too much complex php page could have done that... but I just can't find it...

As for dedicated, I don't have problem paying less than 90$ by month... but good dedicated are often more like 125$ and up. And I'm not sure I'm ready to manage a server like this alone.

[thisisit3]

An SDX server is definitely more powerful than any VPS, in simple terms your VPS has the cpu power of a Pentium 2 at least thats what my tests show on my VPS servers.

Now on to your performance problem...

Its possible that your problem is related to simple Denial of Service, which could be the result of a web crawler or search engine. There are ways to stop apache from causing problems, for example you can limit the number of processes/threads its spawns or limit the maximum number of clients it will serve.

If you had a dedicated server then you could use iptables to limit access based on packets and IP's per second and other cool tricks like that. Unfortunately the required iptables modules are not available on a VPS (as far as tech support has told me when i asked them to install them on our VPS servers), but are installed by default on dedicated servers with CentOS.