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19
votes
3answers
14k views

Linux - How can I see what's waiting for disk IO

I have a server that has a really high load. Nothing is jumping out at me in terms of CPU usage, and it's not swapping. I think it's cause some processes are waiting for disk IO, and I want to see ...
17
votes
6answers
13k views

Optimize apache/php/mysql running on VPS for heavy load

Question about optimizing an apache/mysql server on a VPS with 512m of RAM. Under normal load everything runs fast, no connection lag. However when we get our heavy traffic days (50k+ visits) the ...
10
votes
4answers
5k views

Load Balancing a UDP server

I have a udp server, it is a central part in my business process. in order to handle the loads I'm expecting in the production environment I'll probably need 2 or 3 instances of the server. The server ...
9
votes
3answers
631 views

Load avg weirdness on Linux Ubuntu

In past few days I've been trying to understand the weirdness which is happening in our infrastructure but I haven't been able to figure it our so I'm turning to you guys to give me some hints. I've ...
8
votes
6answers
2k views

How high can system load go?

Every time I login to my servers via SSH it flashes me a bit of server info. IE IP Address, Swap Usage, Memory Usage, etc. One of the other things it flashes me is System Load. Now most of the time ...
8
votes
6answers
3k views

How to find the cause for growing server load

I'm having load problems with my server and even though I'm a somewhat experienced Linux admin I'm out of ideas now. The problem is a slowly but steadily increasing load on the server without any ...
7
votes
3answers
10k views

Linux disk IO load breakdown, by filesystem path and/or process?

Does anyone have experience with a tool that can provide an indication of disk IO load by filesystem path. I use to 'iostat' utility, frequently, to learn how much disk activity is taking place on a ...
7
votes
3answers
544 views

Do you run antivirus in mail server?

Considering a normal e-mail volume (I don't know how can I define that) of 10000 users in a mail server does it make sense to scan emails for viruses? I guess it should affect the server load but in ...
7
votes
3answers
896 views

What are some ways to prevent user cron jobs from crushing the servers?

It happens fairly frequently that user cron jobs on shared servers all run at the same time and get caught in contention (near as I've been able to tell). So load explodes, Nagios is angry, Apache ...
7
votes
3answers
591 views

Record load time of web pages

I have been asked to investigate a way of record how long it a full page request is on our website. i.e. how long it takes from when a user clicks on a link till the page has finished loading. Now ...
6
votes
7answers
784 views

When to Add another server(s)

When is the right time to start adding(or thinking about adding) servers to your Web Application? What are the difficulties involved in going from a single server(DB and Web) to multiple? For ...
6
votes
6answers
803 views

Site Goes Offline Every Day At Midnight - No One Knows Why

Seems every day a website I manage has been going online and offline between 12a and 12:25a. I have no idea what is causing the issue so I am seeking guidance on where to start. It is a Wordpress ...
6
votes
6answers
223 views

solution to a too much traffic problem

My company has a web service api which is starting to get a lot of use. Recently we had some issues with running out of memory. We optimized some inefficient code and solved the problem. We know we ...
6
votes
5answers
7k views

How can you test that load balancing is working correctly?

We are rolling out our application suite onto different sites around North America and the United Kingdom. We have put a regional load balancers in place with ratios set to separate the load between ...
5
votes
2answers
547 views

Load Average above 20 for single core vps on debian

OS: Debian 6.0 RAM:3072 M, CPU:single core. top: top - 08:56:43 up 21 days, 12:37, 1 user, load average: 28.38, 22.48, 15.95 Tasks: 8 total, 1 running, 7 sleeping, 0 stopped, 0 zombie ...
5
votes
2answers
335 views

explain server load

I have got a managed server with a AMD Phenom QuadCore 3000 + 8 GB RAM I heard that s.th beetween 1-2 server load is 100% workload. My current results there are: 1.27 | 0.8 | 0.78 and in the overal ...
5
votes
8answers
3k views

Apache gets “clogged” with certain requests

I have a very odd intermittent issue. It occurs on a shared hosting server running CentOS and Apache/2.2.8, serving mostly PHP based websites at a rate of between 10 - 30 requests/sec. 3.5 GB RAM, ...
5
votes
5answers
955 views

Ubuntu Server 12.04 CPU Load

I have a Server (2x Hexa-Core Xeon E5649 2.53GHz w/HT with 32GB RAM and 20000 GB Bandwidth) running Ubuntu Server 12.04 LTS. The server runs LAMP and serves one website only, the estimated number of ...
5
votes
2answers
362 views

Is this a reasonable architecture for a newspaper site?

We run a newspaper-style site and are consolidating our architecture from one that grew amorphously into a more scalable, resiliant solution. I was thinking of the following: internet | h/w ...
5
votes
2answers
1k views

Has anyone used uwsgi nginx and django for a high-load environment?

I was wondering if anyone has used uwsgi with nginx to serve a high-load django site before. If so, did they have any problems?
4
votes
6answers
614 views

Effect of distance from server on page load speed

I measured the load speed of a static image file severed by nginx from my server (using pingdom service). The server should normally process this request within few seconds. My server is located in ...
4
votes
7answers
6k views

Acceptable load average

We deployed our new Linux/Exim/Spamassassin mail server on Friday (always a good idea to deploy the day before a long weekend when no admins are around). The load has been hovering around 1.3 on the ...
4
votes
7answers
4k views

High CPU load but top processes in top all around 0%

We have a server with unusual high load and cpu util, but we can't figure out why. When we run top all the procs seem to be very low cpu. http://cl.ly/2d1g0K3q261r0R0K3e35 Is there a better way to ...
4
votes
2answers
255 views

High Server Load cannot figure out why [closed]

My server is currently running CentOS 5.2, with WHM 11.34. Currently, we're at 6.43 to 12 for a load average. The sites that we're hosting are taking a lot time to respond and resolve. top doesn't ...
4
votes
1answer
176 views

What's the effect of iptables/ufw deny filters on server load?

I'm wondering how scalable it is to add IP addresses or subranges I want to block into ufw. E.g., I do this whenever I discover a particularly bad bot or server farm. As my list grows, I wonder how ...
4
votes
2answers
10k views

Limit Apache 2 Memory Usage

I am running a hobby webserver off of an ancient Blue & White G3/300 running Debian PPC Squeeze 2.6.30. The performance is okay for a while after a restart, but it eventually gets more and more ...
4
votes
3answers
513 views

Which user is hogging the MySQL database server's CPU?

I maintain webhosting servers and more often than not sometimes a server slows up as a result of increase in load or a large amount of CPU resources used up. I've observed that its the MySQL usage ...
4
votes
1answer
480 views

How is load average related to CPU utilization?

I am facing a load average of > 3 since past 2 days. The CPU utilization is never above 40 % in all cases. Here are some screenshots of Server Density monitoring tool that I use. The process ...
4
votes
2answers
5k views

What does load average mean? [duplicate]

Possible Duplicate: How to understand the memory usage and load average in linux server I have ready many articles that try to explain load average. To date none have ever explained it well ...
4
votes
1answer
2k views

haproxy httpchk multiple check on backend

is it possible to check two conditions on one backend? example backend web-static option httpchk GET /path/alive.php HTTP/1.1\r\nHost:\ www1.domain.com option httpchk GET ...
3
votes
2answers
619 views

Laggy server, seems iptables is doing the load

I added a few thousand IPs packed in multiple /24 classes to a CentOS box and because of that I am getting scanned day and night. Since this server will be a workhorse and it will only need to be ...
3
votes
1answer
261 views

DNS servers and load balancing

I'm wondering if a simple DNS server could offer, even a limited amount, of load balancing capability. I have a couple of servers and I've been told that multiple IPAddresses can be associated with ...
3
votes
4answers
778 views

Optimizing apache server load

We have an issue with a dedicated server load. We have 16 processors with 4 core @ 2.40GHz, if I understood correctly cat /proc/cpuinfo output. Unfortunately, I don't have access to free -m or ...
3
votes
1answer
317 views

Measuring load - %CPU in top is different than %us

When I run TOP on a remote server, I see a very small system utilization (3.8%us). However, for the actual process I am seeing 29.6% of the CPU. Since this server has 8 CPU cores, is the %CPU the ...
3
votes
3answers
124 views

We are moving to two servers from one server due to performance issues. How do we monitor the value of this change?

We are moving to two servers from one server due to performance issues. We are moving our MySQL DB to its own dedicated server and will keep the original machine as the front end machine running ...
3
votes
3answers
3k views

Could high MaxClient value cause CPU load issues no matter actual server stress caused by visits?

I thought MaxClients is just a limit and when the server hits the limit, it shows blank pages for some people preventing the overload. Also I thought it's just a limit, so the spare connections ...
3
votes
3answers
2k views

High Load - Low IO - Low CPU usage

I have a system whose load is rather high. As you can see from the top output below, CPU usage and I/O is negligible: top - 17:31:59 up 4 days, 2:34, 2 users, load average: 1.00, 0.99, 1.00 ...
3
votes
2answers
3k views

Load Balancing long running TCP connections

I'm trying to research the best way to load balance long running TCP connections for the following scenario: We have multiple servers behind a redundant set of firewalls and clients establish long ...
3
votes
3answers
417 views

Is the system load tied directly to CPU usage?

It's a dual-core machine and the load is around 24 but CPU usage is bouncing around from 60-80% and never reaching 100% so how can there be that many processes waiting? I/O is pretty much nill since ...
3
votes
1answer
80 views

Daemon to manage maintenance scripts

I have a bunch of "night shift scripts" to maintain a server. The problem is, the "action window", when those scripts may run is always different. Sometimes there's nothing going on for minutes and ...
3
votes
1answer
131 views

Open source software for resource management

I recently wrote some scientific software designed to be run from the command line, and am now working on creating a web front end for that software to make it more accessible to scientists who aren't ...
3
votes
1answer
1k views

How can I find the source of my high load issues on Ubuntu server?

We have an Ubuntu 10.4 VPS serving a Rails site which often shows pretty high load, but doesn't have high CPU or memory numbers. Reading a lot of other questions here on Server Fault suggests to me ...
3
votes
2answers
897 views

apache process count spike bringing vm to its knees

we have a few virtual machines we're using as a plesk hosting servers. one of them exhibits the following bad behaviour: apache process count goes sky-high (ive limited MaxClients to 80 to try to ...
3
votes
3answers
103 views

Running a process within a limited amount of resources, in Linux

Is there a way to run a process (e.g. ls, du, find .. etc) within a strictly limited amount of resources (i.e. cpu, memory, I/O) aside from using nice & ionice, as I didn't find them effective ...
3
votes
2answers
204 views

Nagios load spike every 7 hours

I have a NagiosXi server monitoring 631 services on 63 hosts. Every seven hours the load on the server spikes up to 20ish and then gradually falls back to near-0. There are no cron jobs running every ...
3
votes
2answers
256 views

How would I show a static “over capacity” page in IIS?

I'm launching a new site soon and I expect it to make it into mainstream media. At this point, I'm not sure our server will be able to handle all of the requests. Is there a way that I can detect the ...
3
votes
2answers
420 views

Apache 2.4.9 100% CPU load of random workers

I own a t1.micro EC2 instance. After release upgrade of Ubuntu to saucy I got Apache 2.4.6 and I started noticing 100% CPU load like this top - 19:37:58 up 2:55, 2 users, load average: 3.90, 2.90, ...
2
votes
4answers
572 views

Why my server has high load despite mere 1.5% CPU usage

In this is what whm apache status says: Current Time: Sunday, 23-Dec-2012 05:13:40 CST Restart Time: Saturday, 22-Dec-2012 13:38:12 CST Parent Server Generation: 9 Server uptime: 15 hours 35 minutes ...
2
votes
4answers
479 views

Tracking down load average

The "load average" on a *nix machine is the "average length of the run queue", or in other words, the average number of processes that are doing something (or waiting to do something). While the ...
2
votes
2answers
300 views

LAMP stack on 64bit, 16 core box chews up 100% CPU

===SOLVED=== This issue was solved. Turns out that ImageMagick has trouble with multiple CPUs. Compiling ImageMagick to use one CPU solved the problem. ================ I added a new web server as ...