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  • Load balance incoming traffic

    - by justin
    Dear All Please I have the following scenario. 3 servers voip / mail / terminal one load balancing router 2 internet connections (static ip`s) My concern is to load balance incoming traffic since the outgoing traffic is being taking care by the load balancing router. For instance all offices connect to the mail server via the internet same for voip and terminal services. The mail and voip clients are set up with one of the static ip`s and the router forwards the request to the appropriate server. But obviously like this there is no fail over nor load balancing cause all requests are being directed to one internet connection. Anyone has a suggestion was thing of a dns server, does this make sens ? or maybe a hosted option ? Thanks Justin

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  • Coldfusion 8 Application Crashes Under Heavy Load

    - by KM01
    Hello, We have a CF8 app that runs for 20-25 minutes before crashing under heavy load ~ 1200 users. This load is generated by our load testing tool: 1200 users ramped up in 5 mins (approx behavior of our users), running for an hour. We have this app on Solaris 10, Apache 2, JRun 4 and Oracle 10g. Java version is 1.6. During the initial load tests, the thread dumps pointed to monitor deadlocks that pointed to sessions. "jrpp-173": waiting to lock monitor 0x019fdc60 (object 0x6b893530, a java.util.Hashtable), which is held by "scheduler-1" "scheduler-1": waiting to lock monitor 0x026c3ce0 (object 0x6abe2f20, a coldfusion.monitor.memory.SessionMemoryMonitor$TopMemoryUsedSessions), which is held by "jrpp-167" "jrpp-167": waiting to lock monitor 0x019fdc60 (object 0x6b893530, a java.util.Hashtable), which is held by "scheduler-1" We increased the number of sessions relative to the number of CPUs (48 simultaneous threads against 32 CPUs), and the deadlock went away. While varying the simultaneous threads helped a little bit in terms of response time, the CF server still tanked in 20-25 minutes during all of these tests. We ran more thread dumps, and saw a thread locking a monitor, for e.g.: "jrpp-475" prio=3 tid=0x02230800 nid=0x2c5 runnable [0x4397d000] java.lang.Thread.State: RUNNABLE at java.util.HashMap.getEntry(HashMap.java:347) at java.util.HashMap.containsKey(HashMap.java:335) at java.util.HashSet.contains(HashSet.java:184) at coldfusion.monitor.memory.MemoryTracker.onAddObject(MemoryTracker.java:124) at coldfusion.monitor.memory.MemoryTrackerProxy.onReplaceValue(MemoryTrackerProxy.java:598) at coldfusion.monitor.memory.MemoryTrackerProxy.onPut(MemoryTrackerProxy.java:510) at coldfusion.util.CaseInsensitiveMap.put(CaseInsensitiveMap.java:250) at coldfusion.util.FastHashtable.put(FastHashtable.java:43) - locked <0x6f7e1a78> (a coldfusion.runtime.Struct) at coldfusion.runtime.CfJspPage._arrayset(CfJspPage.java:1027) at coldfusion.runtime.CfJspPage._arraySetAt(CfJspPage.java:2117) at cfvalidation2ecfc1052964961$funcSETUSERAUDITDATA.runFunction(/app/docs/apply/cfcs/validation.cfc:377) As you see in the last line above there were several references CFMs and CFCs, and the lines have "cflock" tags, which were scoped to the "application." We (the dev team) then changed them to be scoped to a "name". After more load tests, there is no locking going on and there no deadlocks, but now the application tanks in 7-10 minutes. We've gotten system, network and DB reports from the respective admins, and they are not being taxed; even watched the server stats with server monitor, top, prstat, ran sar reports, etc. So we believe it is an issue with the CF server or maybe the JVM. I am running out of ideas as to what else we can try. Disclaimer: I am not a CF developer or Admin. I am just running the load test, analyzing the reports, threads etc, and sharing the results with the dev and admin teams, and trying the next change, and so on. So far no dice. Has anyone run into something similar? How did you go about diagnosing and troubleshooting? All thoughts and pointers welcome. Thank you for your time! KM

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  • Perform action based on load avg

    - by sfx
    I'm running some web applications on an debian server and have to struggle with ddos attacks sometimes. It's eating up all my resources and I can't ssh anymore into the server. An idea was to drop all connections if the load avg is too high, so there are still resources for me and accept new connections if the load avg is low enough. Since this has to work under heavy load I'm afraid a cronjob wouldn't be fast enough or take too much resources. tl;dr: Is there a way to configure the behavior if the load avg is above a specific threshold?

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  • No apparent reason for high load average

    - by Oz.
    We have several web servers running on Amazon (ec2) c1.xlarge, over Amazon AMI. The servers are duplicates of each other, running the exact same hardware and software. Each server spec is: 7 GB of memory 20 EC2 Compute Units (8 virtual cores with 2.5 EC2 Compute Units each) 1690 GB of instance storage 64-bit platform I/O Performance: High API name: c1.xlarge A couple of weeks ago we have run a yum upgrade on one of the servers. Starting on this upgrade the upgraded server started showing a high load average. Needless to say, we did not update the other servers and we can not do so until we understand the reason for this behavior. The strange thing is that when we compare the servers using top or iostat, we can not find the reason for the high load. Note that we have moved traffic from the "problematic" server to the others, which have made the "problematic" server less crowded in terms of requests, and still his load is higher. Do you have any idea what could it be, or where else can we check? Many thanks for the help! Oz. # # proper server # w command # 00:42:26 up 2 days, 19:54, 2 users, load average: 0.41, 0.48, 0.49 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT pts/1 82.80.137.29 00:28 14:05 0.01s 0.01s -bash pts/2 82.80.137.29 00:38 0.00s 0.02s 0.00s w # # proper server # iostat command # Linux 3.2.12-3.2.4.amzn1.x86_64 _x86_64_ (8 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 9.03 0.02 4.26 0.17 0.13 86.39 Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn xvdap1 1.63 1.50 55.00 367236 13444008 xvdfp1 4.41 45.93 70.48 11227226 17228552 xvdfp2 2.61 2.01 59.81 491890 14620104 xvdfp3 8.16 14.47 94.23 3536522 23034376 xvdfp4 0.98 0.79 45.86 192818 11209784 # # problematic server # w command # 00:43:26 up 2 days, 21:52, 2 users, load average: 1.35, 1.10, 1.17 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT pts/0 82.80.137.29 00:28 15:04 0.02s 0.02s -bash pts/1 82.80.137.29 00:38 0.00s 0.05s 0.00s w # # problematic server # iostat command # Linux 3.2.20-1.29.6.amzn1.x86_64 _x86_64_ (8 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 7.97 0.04 3.43 0.19 0.07 88.30 Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn xvdap1 2.10 1.49 76.54 374660 19253592 xvdfp1 5.64 40.98 85.92 10308946 21612112 xvdfp2 3.97 4.32 93.18 1087090 23439488 xvdfp3 10.87 30.30 115.14 7622474 28961720 xvdfp4 1.12 0.28 65.54 71034 16487112

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  • Insufficient channel capacity of 1GBit

    - by Roman S
    There is a Caching Server (Varnish): it receives data from Amazon S3 on request, saves it for some time and gives it to the client. We have encountered the problem of insufficient channel capacity of 1GBit. Peak load within 4 hours completely chokes the channel. Server performance is sufficient for now. Approximately 4.5TB of data are transmitted per day. More than 100TB are accumulated per month. The first thought that comes to mind is simply to add one more 1GBit port and sleep peacefully until 2GBit are not enough (it may happen quite quickly) or one server is not able to handle it. And then we just need to add new Caching Servers. But now we need a Load Balancer, which will send requests on one and the same URL, always on one and the same server (to avoid multiple copies of the same cached objects). Here are the questions: Does a Balancer need a band equal to sum of all bands of Caching Servers? What shall we do in case there are no ports in a Balancer? Should we add more Balancers or solve the problem by means of Round robin DNS? What are the standard approaches to such problems? Can anyone advise hosting-companies, which can solve this problem? We are interested in American and European markets.

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  • Load Balancing Linux Web Services and Change Config Without Restart

    - by Eric J.
    What options are available to load balance web service traffic on Linux with the ability to add or remove servers from the server pool without restarting the load balancer? This post: http://serverfault.com/questions/71437/mod-proxy-change-without-restart looks like a very promising way to switch between two servers, but I don't know enough about mod_proxy and mod_rewrite to understand how/if I can use an external file to specify the BalancerMember entries for a section. Are there other open source load balancers that support reconfiguration without restart?

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  • Load balancing + NAT issue on BNT GBE 2-7 gear

    - by Clément Game
    Hi guys, I've got troubles configuring an Hardware load-Balancer with NAT functions. I have the following architecture: Internet === VIP (public) LB (private ip) ==== private addressed servers When a connection is initialised from the outside (internet) , the LB correctly forwards the SYN packet to one of the private servers. But when these servers want to reply with a SYN/ACK there is a problem. the initial SYN packet had as ip header : VIP = Private_server_Address But the private servers cannot reach VIP from their side (this is normal since it's nated), and then provide a correct reply. Have you guys any solution to correctly forward the packets to their correct destination ? Note: The load balancer, which is the default gw for the servers, also has a NAT rule for "masquerading" (actually more SNAT than real masquerading) Regards, Clément.

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  • Sticky Load Balancing with AWS

    - by John Wheal
    I have just setup a load balancer with AWS for a few instances as search engine crawlers were bringing down the site (it has millions of pages). Parts of the site allow you to login so I selected: Enable Application Generated Cookie Stickiness and everything works fine. I now wonder how this will effect my SEO and the crawlers. As I selected sticky load balancing does this mean that a crawler will be stuck on one server and therefore defeat the point in the load balancer? Any recommendations will be appreciated.

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  • Load testing nginx inside AWS

    - by andy
    I'm trying to load test nginx running on AWS. I need to try to optimise it to handle 1Gbps of inbound traffic. Currently I've got it to peak at 85Mbit/s by running nginx on an m1.large with 4 other machines hitting it by using ab with -i (for head requests) -k (keepalives) -r (ignore failed requests) -n 500000 -c 20000. I'm struggling to generate more than 85 Mbit/s traffic from 4 machines, yet when I do scp a large file I get nearly 0.25Gbit/s of traffic going over the network. Are there any tools or approaches that I could use to load test nginx that might generate more load? I'm only interested in inbound traffic, so perhaps a DoS tool could help if it chucks away responses? I'm hitting a very small (40 byte) static asset, and have peaked at handling 50K concurrent connections and getting 25k reqs/s when just using a single load generator machine.

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  • What other ways can I load balance EC2 servers without using Elastic Load Balancing?

    - by undefined
    I have a web application that consists of a web server managed by a web hosting firm, a set of EC2 instances in amazons cloud and a MySQL database (hosted on the webserver). MySQL is behind a firewall and is set to allow access from Localhost and from a single IP address which is an Amazon Elastic IP address that is attached to the EC2 instance I have been running up to now. The problem is that I want to look at my scaling up and load balancing strategy for my EC2 instance. To this end I have been investigating the Elastic Load Balancers and Autoscaling tools that Amazon provides and have managed to set this up fine but for one thing - connecting to the MySQL database running on my webserver. I realised (thanks to answers on Serverfault) that I needed to check firewall settings and add the IP address for the load balancer, however Elastic Load Balancers provide you with a DNS name, not an IP address and infact the IP addresses change over time so this will not work. I have been told by the company hosting the database that the way the firewall works is to look up the IP address of the DNS name and store the IP rather than the DNS name. so basically this will not work and the only way to allow access would be to open up the SQL port to allow access from anyone! Is this a viable idea? Should I look at moving my database into the cloud? Is there another firewall that the server company can use? Should I find another way of load balancing (if so what?) tricky one eh? any help appreciated!

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  • Load balanced proxies to avoid an API request limit

    - by ClickClickClick
    There is a certain API out there which limits the number of requests per day per IP. My plan is to create a bunch of EC2 instances with elastic IPs to sidestep the limitation. I'm familiar with EC2 and am just interested in the configuration of the proxies and a software load balancer. I think I want to run a simple TCP Proxy on each instance and a software load balancer on the machine I will be requesting from. Something that allows the following to return a response from a different IP (round robin, availability, doesn't really matter..) eg. curl http://www.bbc.co.uk -x http://myproxyloadbalancer:port Could anyone recommend a combination of software or even a link to an article that details a pleasing way to pull it off? (My client won't be curl but is proxy aware.. I'll be making the requests from a Ruby script..)

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  • Squid on windows loadbalancing only to one server

    - by Martin L.
    After thousands of googles and trying days i cant get the load balancer/failover in squid on windows to work. Iam using squid 2.7. My webservers are 2 single NIC lighttpd and one dual nic lighttpd. server1 in this example is running squid on port 80 and lighttpd on port 8080 (just to test) Requirements: All 3 webservers running lighttpd should be balanced two option for load balancing: Best would be if server1 is busy server2 takes over, if server2 is busy server3 takes over, etc.. Round robin style evenly distributed load. Eg server1 takes first call, server2 second etc.. All requests should be treated the same way (no url rewriting or so on) Sent host headers have to be redirected to every server as http host header, speaking of "server1", "server1.company.internal" and "10.211.1.1". My approach: acl all src all acl manager proto cache_object http_port 80 accel defaultsite=server1.company.internal vhost #reverse proxy entries cache_peer 10.211.2.1 parent 8080 0 no-query originserver round-robin login=PASS name=server1_nic1 cache_peer 10.211.1.2 parent 80 0 no-query originserver round-robin login=PASS name=server2_nic1 cache_peer 10.211.2.3 parent 8080 0 no-query originserver round-robin login=PASS name=server3_nic1 cache_peer 10.211.2.4 parent 8080 0 no-query originserver round-robin login=PASS name=server3_nic2 #decl of names of squid host acl registered_name_hostdomain dstdomain server1.company.internal acl registered_name_host dstdomain server1 #ip of squid host acl registered_name_ip dstdomain 10.211.2.1 # access: redirects the correct squid hostname http_access allow registered_name_hostdomain http_access allow registered_name_host http_access allow registered_name_ip http_access deny all cache_peer_access server1_nic1 allow registered_name_hostdomain cache_peer_access server1_nic1 allow registered_name_host cache_peer_access server1_nic1 allow registered_name_ip cache_peer_access server2_nic1 allow registered_name_hostdomain cache_peer_access server2_nic1 allow registered_name_host cache_peer_access server2_nic1 allow registered_name_ip cache_peer_access server3_nic1 allow registered_name_hostdomain cache_peer_access server3_nic1 allow registered_name_host cache_peer_access server3_nic1 allow registered_name_ip cache_peer_access server3_nic2 allow registered_name_hostdomain cache_peer_access server3_nic2 allow registered_name_host cache_peer_access server3_nic2 allow registered_name_ip cache_peer_access server1_nic1 deny all cache_peer_access server2_nic1 deny all cache_peer_access server3_nic1 deny all cache_peer_access server3_nic2 deny all never_direct allow all Problems: Load balancer does not load balance other than to first server. Only if the first server is killed in any way the second will take over. I have seen the others working at some point, but definitely not as the intended load balancing described above. If the cache_peer_access is not defined sometimes the wrong hostname is sent to the backend webserver and this always depends on the defaultsite= parameter. Probably because the host header on the request to squid is not set and its replaced by defaultsite. Leaving out defaultsite didnt solve the problem. The only workaround i found for this is the current approach with cache_peer_access. Questions: Does the cache_peer_access influence the round-robin? Is there a better workaround to pass the host header to the backed webservers? Which parameters do increase the speed of load balancing or does anyone have a better approach? -Martin

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  • West Wind WebSurge - an easy way to Load Test Web Applications

    - by Rick Strahl
    A few months ago on a project the subject of load testing came up. We were having some serious issues with a Web application that would start spewing SQL lock errors under somewhat heavy load. These sort of errors can be tough to catch, precisely because they only occur under load and not during typical development testing. To replicate this error more reliably we needed to put a load on the application and run it for a while before these SQL errors would flare up. It’s been a while since I’d looked at load testing tools, so I spent a bit of time looking at different tools and frankly didn’t really find anything that was a good fit. A lot of tools were either a pain to use, didn’t have the basic features I needed, or are extravagantly expensive. In  the end I got frustrated enough to build an initially small custom load test solution that then morphed into a more generic library, then gained a console front end and eventually turned into a full blown Web load testing tool that is now called West Wind WebSurge. I got seriously frustrated looking for tools every time I needed some quick and dirty load testing for an application. If my aim is to just put an application under heavy enough load to find a scalability problem in code, or to simply try and push an application to its limits on the hardware it’s running I shouldn’t have to have to struggle to set up tests. It should be easy enough to get going in a few minutes, so that the testing can be set up quickly so that it can be done on a regular basis without a lot of hassle. And that was the goal when I started to build out my initial custom load tester into a more widely usable tool. If you’re in a hurry and you want to check it out, you can find more information and download links here: West Wind WebSurge Product Page Walk through Video Download link (zip) Install from Chocolatey Source on GitHub For a more detailed discussion of the why’s and how’s and some background continue reading. How did I get here? When I started out on this path, I wasn’t planning on building a tool like this myself – but I got frustrated enough looking at what’s out there to think that I can do better than what’s available for the most common simple load testing scenarios. When we ran into the SQL lock problems I mentioned, I started looking around what’s available for Web load testing solutions that would work for our whole team which consisted of a few developers and a couple of IT guys both of which needed to be able to run the tests. It had been a while since I looked at tools and I figured that by now there should be some good solutions out there, but as it turns out I didn’t really find anything that fit our relatively simple needs without costing an arm and a leg… I spent the better part of a day installing and trying various load testing tools and to be frank most of them were either terrible at what they do, incredibly unfriendly to use, used some terminology I couldn’t even parse, or were extremely expensive (and I mean in the ‘sell your liver’ range of expensive). Pick your poison. There are also a number of online solutions for load testing and they actually looked more promising, but those wouldn’t work well for our scenario as the application is running inside of a private VPN with no outside access into the VPN. Most of those online solutions also ended up being very pricey as well – presumably because of the bandwidth required to test over the open Web can be enormous. When I asked around on Twitter what people were using– I got mostly… crickets. Several people mentioned Visual Studio Load Test, and most other suggestions pointed to online solutions. I did get a bunch of responses though with people asking to let them know what I found – apparently I’m not alone when it comes to finding load testing tools that are effective and easy to use. As to Visual Studio, the higher end skus of Visual Studio and the test edition include a Web load testing tool, which is quite powerful, but there are a number of issues with that: First it’s tied to Visual Studio so it’s not very portable – you need a VS install. I also find the test setup and terminology used by the VS test runner extremely confusing. Heck, it’s complicated enough that there’s even a Pluralsight course on using the Visual Studio Web test from Steve Smith. And of course you need to have one of the high end Visual Studio Skus, and those are mucho Dinero ($$$) – just for the load testing that’s rarely an option. Some of the tools are ultra extensive and let you run analysis tools on the target serves which is useful, but in most cases – just plain overkill and only distracts from what I tend to be ultimately interested in: Reproducing problems that occur at high load, and finding the upper limits and ‘what if’ scenarios as load is ramped up increasingly against a site. Yes it’s useful to have Web app instrumentation, but often that’s not what you’re interested in. I still fondly remember early days of Web testing when Microsoft had the WAST (Web Application Stress Tool) tool, which was rather simple – and also somewhat limited – but easily allowed you to create stress tests very quickly. It had some serious limitations (mainly that it didn’t work with SSL),  but the idea behind it was excellent: Create tests quickly and easily and provide a decent engine to run it locally with minimal setup. You could get set up and run tests within a few minutes. Unfortunately, that tool died a quiet death as so many of Microsoft’s tools that probably were built by an intern and then abandoned, even though there was a lot of potential and it was actually fairly widely used. Eventually the tools was no longer downloadable and now it simply doesn’t work anymore on higher end hardware. West Wind Web Surge – Making Load Testing Quick and Easy So I ended up creating West Wind WebSurge out of rebellious frustration… The goal of WebSurge is to make it drop dead simple to create load tests. It’s super easy to capture sessions either using the built in capture tool (big props to Eric Lawrence, Telerik and FiddlerCore which made that piece a snap), using the full version of Fiddler and exporting sessions, or by manually or programmatically creating text files based on plain HTTP headers to create requests. I’ve been using this tool for 4 months now on a regular basis on various projects as a reality check for performance and scalability and it’s worked extremely well for finding small performance issues. I also use it regularly as a simple URL tester, as it allows me to quickly enter a URL plus headers and content and test that URL and its results along with the ability to easily save one or more of those URLs. A few weeks back I made a walk through video that goes over most of the features of WebSurge in some detail: Note that the UI has slightly changed since then, so there are some UI improvements. Most notably the test results screen has been updated recently to a different layout and to provide more information about each URL in a session at a glance. The video and the main WebSurge site has a lot of info of basic operations. For the rest of this post I’ll talk about a few deeper aspects that may be of interest while also giving a glance at how WebSurge works. Session Capturing As you would expect, WebSurge works with Sessions of Urls that are played back under load. Here’s what the main Session View looks like: You can create session entries manually by individually adding URLs to test (on the Request tab on the right) and saving them, or you can capture output from Web Browsers, Windows Desktop applications that call services, your own applications using the built in Capture tool. With this tool you can capture anything HTTP -SSL requests and content from Web pages, AJAX calls, SOAP or REST services – again anything that uses Windows or .NET HTTP APIs. Behind the scenes the capture tool uses FiddlerCore so basically anything you can capture with Fiddler you can also capture with Web Surge Session capture tool. Alternately you can actually use Fiddler as well, and then export the captured Fiddler trace to a file, which can then be imported into WebSurge. This is a nice way to let somebody capture session without having to actually install WebSurge or for your customers to provide an exact playback scenario for a given set of URLs that cause a problem perhaps. Note that not all applications work with Fiddler’s proxy unless you configure a proxy. For example, .NET Web applications that make HTTP calls usually don’t show up in Fiddler by default. For those .NET applications you can explicitly override proxy settings to capture those requests to service calls. The capture tool also has handy optional filters that allow you to filter by domain, to help block out noise that you typically don’t want to include in your requests. For example, if your pages include links to CDNs, or Google Analytics or social links you typically don’t want to include those in your load test, so by capturing just from a specific domain you are guaranteed content from only that one domain. Additionally you can provide url filters in the configuration file – filters allow to provide filter strings that if contained in a url will cause requests to be ignored. Again this is useful if you don’t filter by domain but you want to filter out things like static image, css and script files etc. Often you’re not interested in the load characteristics of these static and usually cached resources as they just add noise to tests and often skew the overall url performance results. In my testing I tend to care only about my dynamic requests. SSL Captures require Fiddler Note, that in order to capture SSL requests you’ll have to install the Fiddler’s SSL certificate. The easiest way to do this is to install Fiddler and use its SSL configuration options to get the certificate into the local certificate store. There’s a document on the Telerik site that provides the exact steps to get SSL captures to work with Fiddler and therefore with WebSurge. Session Storage A group of URLs entered or captured make up a Session. Sessions can be saved and restored easily as they use a very simple text format that simply stored on disk. The format is slightly customized HTTP header traces separated by a separator line. The headers are standard HTTP headers except that the full URL instead of just the domain relative path is stored as part of the 1st HTTP header line for easier parsing. Because it’s just text and uses the same format that Fiddler uses for exports, it’s super easy to create Sessions by hand manually or under program control writing out to a simple text file. You can see what this format looks like in the Capture window figure above – the raw captured format is also what’s stored to disk and what WebSurge parses from. The only ‘custom’ part of these headers is that 1st line contains the full URL instead of the domain relative path and Host: header. The rest of each header are just plain standard HTTP headers with each individual URL isolated by a separator line. The format used here also uses what Fiddler produces for exports, so it’s easy to exchange or view data either in Fiddler or WebSurge. Urls can also be edited interactively so you can modify the headers easily as well: Again – it’s just plain HTTP headers so anything you can do with HTTP can be added here. Use it for single URL Testing Incidentally I’ve also found this form as an excellent way to test and replay individual URLs for simple non-load testing purposes. Because you can capture a single or many URLs and store them on disk, this also provides a nice HTTP playground where you can record URLs with their headers, and fire them one at a time or as a session and see results immediately. It’s actually an easy way for REST presentations and I find the simple UI flow actually easier than using Fiddler natively. Finally you can save one or more URLs as a session for later retrieval. I’m using this more and more for simple URL checks. Overriding Cookies and Domains Speaking of HTTP headers – you can also overwrite cookies used as part of the options. One thing that happens with modern Web applications is that you have session cookies in use for authorization. These cookies tend to expire at some point which would invalidate a test. Using the Options dialog you can actually override the cookie: which replaces the cookie for all requests with the cookie value specified here. You can capture a valid cookie from a manual HTTP request in your browser and then paste into the cookie field, to replace the existing Cookie with the new one that is now valid. Likewise you can easily replace the domain so if you captured urls on west-wind.com and now you want to test on localhost you can do that easily easily as well. You could even do something like capture on store.west-wind.com and then test on localhost/store which would also work. Running Load Tests Once you’ve created a Session you can specify the length of the test in seconds, and specify the number of simultaneous threads to run each session on. Sessions run through each of the URLs in the session sequentially by default. One option in the options list above is that you can also randomize the URLs so each thread runs requests in a different order. This avoids bunching up URLs initially when tests start as all threads run the same requests simultaneously which can sometimes skew the results of the first few minutes of a test. While sessions run some progress information is displayed: By default there’s a live view of requests displayed in a Console-like window. On the bottom of the window there’s a running total summary that displays where you’re at in the test, how many requests have been processed and what the requests per second count is currently for all requests. Note that for tests that run over a thousand requests a second it’s a good idea to turn off the console display. While the console display is nice to see that something is happening and also gives you slight idea what’s happening with actual requests, once a lot of requests are processed, this UI updating actually adds a lot of CPU overhead to the application which may cause the actual load generated to be reduced. If you are running a 1000 requests a second there’s not much to see anyway as requests roll by way too fast to see individual lines anyway. If you look on the options panel, there is a NoProgressEvents option that disables the console display. Note that the summary display is still updated approximately once a second so you can always tell that the test is still running. Test Results When the test is done you get a simple Results display: On the right you get an overall summary as well as breakdown by each URL in the session. Both success and failures are highlighted so it’s easy to see what’s breaking in your load test. The report can be printed or you can also open the HTML document in your default Web Browser for printing to PDF or saving the HTML document to disk. The list on the right shows you a partial list of the URLs that were fired so you can look in detail at the request and response data. The list can be filtered by success and failure requests. Each list is partial only (at the moment) and limited to a max of 1000 items in order to render reasonably quickly. Each item in the list can be clicked to see the full request and response data: This particularly useful for errors so you can quickly see and copy what request data was used and in the case of a GET request you can also just click the link to quickly jump to the page. For non-GET requests you can find the URL in the Session list, and use the context menu to Test the URL as configured including any HTTP content data to send. You get to see the full HTTP request and response as well as a link in the Request header to go visit the actual page. Not so useful for a POST as above, but definitely useful for GET requests. Finally you can also get a few charts. The most useful one is probably the Request per Second chart which can be accessed from the Charts menu or shortcut. Here’s what it looks like:   Results can also be exported to JSON, XML and HTML. Keep in mind that these files can get very large rather quickly though, so exports can end up taking a while to complete. Command Line Interface WebSurge runs with a small core load engine and this engine is plugged into the front end application I’ve shown so far. There’s also a command line interface available to run WebSurge from the Windows command prompt. Using the command line you can run tests for either an individual URL (similar to AB.exe for example) or a full Session file. By default when it runs WebSurgeCli shows progress every second showing total request count, failures and the requests per second for the entire test. A silent option can turn off this progress display and display only the results. The command line interface can be useful for build integration which allows checking for failures perhaps or hitting a specific requests per second count etc. It’s also nice to use this as quick and dirty URL test facility similar to the way you’d use Apache Bench (ab.exe). Unlike ab.exe though, WebSurgeCli supports SSL and makes it much easier to create multi-URL tests using either manual editing or the WebSurge UI. Current Status Currently West Wind WebSurge is still in Beta status. I’m still adding small new features and tweaking the UI in an attempt to make it as easy and self-explanatory as possible to run. Documentation for the UI and specialty features is also still a work in progress. I plan on open-sourcing this product, but it won’t be free. There’s a free version available that provides a limited number of threads and request URLs to run. A relatively low cost license  removes the thread and request limitations. Pricing info can be found on the Web site – there’s an introductory price which is $99 at the moment which I think is reasonable compared to most other for pay solutions out there that are exorbitant by comparison… The reason code is not available yet is – well, the UI portion of the app is a bit embarrassing in its current monolithic state. The UI started as a very simple interface originally that later got a lot more complex – yeah, that never happens, right? Unless there’s a lot of interest I don’t foresee re-writing the UI entirely (which would be ideal), but in the meantime at least some cleanup is required before I dare to publish it :-). The code will likely be released with version 1.0. I’m very interested in feedback. Do you think this could be useful to you and provide value over other tools you may or may not have used before? I hope so – it already has provided a ton of value for me and the work I do that made the development worthwhile at this point. You can leave a comment below, or for more extensive discussions you can post a message on the West Wind Message Board in the WebSurge section Microsoft MVPs and Insiders get a free License If you’re a Microsoft MVP or a Microsoft Insider you can get a full license for free. Send me a link to your current, official Microsoft profile and I’ll send you a not-for resale license. Send any messages to [email protected]. Resources For more info on WebSurge and to download it to try it out, use the following links. West Wind WebSurge Home Download West Wind WebSurge Getting Started with West Wind WebSurge Video© Rick Strahl, West Wind Technologies, 2005-2014Posted in ASP.NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Possible to redirect from HTTPS to HTTP behind load-balancer?

    - by Derek Hunziker
    I have a basic ASP.NET application that sits behind an F5 load-balancer. Incoming SSL requests (over HTTPS) terminate at the load-balancer and all internal communication between the load-balancer and my application servers is unsecure (over HTTP). When a unsecure request comes in, my app is able to use Response.Redirect("https://...") to redirect a secure URL with no problems. However, the other direction appears to be impossible - I cannot redirect from HTTPS to HTTP using Response.Redirect() from my application. The URL remains HTTPS for the client and does not change. Could the F5 be preventing the redirect for ever reaching the client? Is there any special configuration necessary to let this happen?

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  • Ubuntu Server 12.04 CPU Load

    - by zertux
    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 users is to be ~ 15,000 at the same time. At the moment i have around 2000 users online each of them runs 50 MySQL queries (small values mostly select and insert) from the beginning until the end of the session. Server CPU Load is high at this number of connections while the RAM usage is almost 1GB out of 32GB its worth mentioning that the server was running very fast with no problems at all but am concerned about the load average. http://s12.postimage.org/z7hi6mz3h/photo.png top - 03:02:43 up 9 min, 2 users, load average: 50.83, 30.14, 12.83 Tasks: 432 total, 1 running, 430 sleeping, 0 stopped, 1 zombie Cpu(s): 0.1%us, 0.2%sy, 0.0%ni, 66.5%id, 33.1%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 32939992k total, 3111604k used, 29828388k free, 84108k buffers Swap: 2048280k total, 0k used, 2048280k free, 1621640k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2860 root 20 0 25820 2288 1420 S 3 0.0 0:11.18 htop 1182 root 20 0 0 0 0 D 2 0.0 0:01.46 kjournald 1935 mysql 20 0 12.3g 161m 7924 S 1 0.5 102:31.45 mysqld 11 root 20 0 0 0 0 S 0 0.0 0:00.38 kworker/0:1 1822 www-data 20 0 247m 25m 4188 D 0 0.1 0:01.81 apache2 2920 www-data 20 0 0 0 0 Z 0 0.0 0:01.20 apache2 <defunct> 2942 www-data 20 0 247m 23m 3056 D 0 0.1 0:00.20 apache2 3516 www-data 20 0 247m 23m 3028 D 0 0.1 0:00.06 apache2 3521 www-data 20 0 247m 23m 3020 D 0 0.1 0:00.09 apache2 3664 www-data 20 0 247m 23m 3132 D 0 0.1 0:00.09 apache2 3674 www-data 20 0 247m 23m 3252 D 0 0.1 0:00.06 apache2 3713 www-data 20 0 247m 23m 3040 D 0 0.1 0:00.09 apache2 1 root 20 0 24328 2284 1344 S 0 0.0 0:03.09 init 2 root 20 0 0 0 0 S 0 0.0 0:00.00 kthreadd 3 root 20 0 0 0 0 S 0 0.0 0:00.01 ksoftirqd/0 6 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/0 7 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0 8 root RT 0 0 0 0 S 0 0.0 0:00.00 migration/1 9 root 20 0 0 0 0 S 0 0.0 0:00.00 kworker/1:0 root@server:~/codes# vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 19 0 0 29684012 86112 1689844 0 0 19 590 254 231 48 0 47 5 23 0 0 29704812 86128 1697672 0 0 4 320 11100 8121 77 1 22 0 33 0 0 29671044 86156 1705308 0 0 0 5440 13190 9140 95 1 4 0 33 3 0 29670088 86160 1706288 0 0 0 32932 12275 7297 99 0 1 0 35 0 0 29693456 86188 1710724 0 0 4 676 12701 7867 98 1 1 0 ^C I have not changed any of the default configurations that comes with Ubuntu. Is this load normal for such powerful server ? is there any optimization i can make to Apache/MySQL to minimize the load ? What do you recommend ?

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  • Plesk Postfix Mail Server 9.5.4 very heavy load, 1000s of processes

    - by Eugene van der Merwe
    Our Plesk Linux Ubuntu 64-bit mail server has extremely high load and we don't know how to isolate it. The load was okay will two weeks ago but in the last two weeks it's seriously deteriorated. The mail server has been running for years and we have had sporadic performance issues. Normally we reduce the load by turning off all SPAM checks until the problem is sorted (which sometimes resolves itself). Currently we have turned of real time block lists, SPF checking and we have attempted to turn off SpamAssassin. No matter what we do the SpamAssassin check box stays ticked in the GUI. Out of desperation we have done /etc/init.d/psa-spamassassin stop. For years we haven't been able to do SpamAssassin because it kills the server. We would like to use it but performance is more important for now. We cannot turn off Greylisting. The moment we turn off Greylisting our help desk is inandated with calls. Out of desperation we investigated truncating the Greylisting database which is now 2.5 GB big but we abandoned this after noticing turning of Greylisting doesn't improve the performance at all. We have no anti-virus. It's just more load and Dr. Web never really worked that well for us. But we'll try that if it will make a difference. We have implemented Postfix Anvil. This seems to have made the situation worse so we disabled it. We’re not sure if this is the case. Our current mail server is configured to forward all SMTP to a relay server. We did so to reduce the load. This helped a lot because outgoing queues are generally empty. We are running in an Expand configuration. The mail server has about 12 000 accounts of which maybe half are active. We have read through this document: http://www.postfix.org/STRESS_README.html but there are too many settings and we don’t know which ones to choose. Please assist urgently. We need advice on how to fix this problem before all our clients abandon is. The only clue we have is that there are 100s of these processes: 30 13205 1 0 13:18 ? 00:00:00 /usr/lib/plesk-9.0/postfix-queue 127.0.0.1 10027 before-queue 30 13207 1 0 11:38 ? 00:00:00 /usr/lib/plesk-9.0/postfix-queue 127.0.0.1 10027 before-queue 30 13208 1 0 13:18 ? 00:00:00 /usr/lib/plesk-9.0/postfix-queue 127.0.0.1 10026 before-remote 30 13209 1 0 11:38 ? 00:00:00 /usr/lib/plesk-9.0/postfix-queue 127.0.0.1 10026 before-remote 30 13213 1 0 13:18 ? 00:00:00 /usr/lib/plesk-9.0/postfix-queue 127.0.0.1 10027 before-queue

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  • SSI includes not working on Debian with Apache

    - by Mike
    I'm trying to get SSI to work on Debian running Apache, however the .shtml files are not being parsed. From a PHP file with phpinfo() I can see that the following show up in the loaded modules section: mod_mime_xattr mod_mime mod_mime_magic In /etc/apache2/mods-enabled/mime.conf I have (among other things): AddType text/html .shtml AddOutputFilter INCLUDES .shtml In /etc/apache2/sites-enabled/domain.com.conf (for the virtual host in question) I have: <Directory /home/username/public_html> Options +Includes allow from all AllowOverride All </Directory> and for good measure, I added the following as well: <Directory /> Options +Includes </directory> In the user's .htaccess file, I tried adding: Options +Includes AddType text/html shtml AddHandler server-parsed shtml Nothing seems to work. How can I even debug this? Edit: Here is the output of ls /etc/apache2/mods-enabled/ in case this helps actions.conf dav_svn.load proxy_balancer.load actions.load deflate.conf proxy.conf alias.conf deflate.load proxy_connect.load alias.load dir.conf proxy_http.load auth_basic.load dir.load proxy.load auth_digest.load env.load python.load authn_file.load fcgid.conf reqtimeout.conf authz_default.load fcgid.load reqtimeout.load authz_groupfile.load mime.conf rewrite.load authz_host.load mime.load ruby.load authz_user.load mime_magic.conf setenvif.conf autoindex.conf mime_magic.load setenvif.load autoindex.load mime-xattr.load ssl.conf cgi.load negotiation.conf ssl.load dav_fs.conf negotiation.load status.conf dav_fs.load php5.conf status.load dav.load php5.load suexec.load dav_svn.conf proxy_balancer.conf

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  • High load average, low CPU and IO (Centos 5.7)

    - by Ben
    A Drupal 7 site with CiviCRM, after running smoothly for a year on a 1&1 VPS suddenly became unresponsive. Now pages eventually load, but can take more than a minute. Looking at resource use in Virtuozzo, the load average carries a warning, and has remained above 1. While I understand this isn't particularly high, this is a change from when the site was working. Here is a typical snapshot of top: top - 03:10:32 up 3:21, 1 user, load average: 1.16, 1.22, 1.30 Tasks: 43 total, 1 running, 42 sleeping, 0 stopped, 0 zombie Cpu(s): 0.1%us, 0.1%sy, 0.1%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 2097152k total, 1015112k used, 1082040k free, 0k buffers Swap: 0k total, 0k used, 0k free, 0k cached CPU idle level never seems to go much below 70%. wa is virtually always at 0. There appears to be lots of free memory. And here is some vmstat output, again showign wa at 0, plenty of free memory, and an idle CPU: procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 2 0 0 1100872 0 0 0 0 2783 23672 0 538 1 0 99 0 0 1 0 0 1100872 0 0 0 0 0 16 0 101754 0 0 100 0 0 0 0 0 1100872 0 0 0 0 0 17 0 103133 0 0 100 0 0 0 0 0 1100872 0 0 0 0 0 1 0 102080 0 0 100 0 0 1 0 0 1100872 0 0 0 0 0 6 0 99881 0 0 100 0 0 0 0 0 1100872 0 0 0 0 0 1 0 105187 0 0 100 0 0 I've spoken to 1&1 but they don't have any ideas as to what could be causing the high load average. Instead they suggested an upgrade :) I've looked for processes that might be causing this, examined MySQL showprocesslist, and restarted the container with no result. Does anyone have more troubleshooting suggestions or insights?

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  • Virtualbox HTTP load testing, host CPU overload issues

    - by aschuler
    I'm doing HTTP load testing benchmarks (using Apache Benchmark and Siege) on a small Java EE 1.7.0 / Tomcat 7.0.26 application running on a Debian Squeeze 6.0.4 x64 virtualized with Virtualbox 4.1.8. The computer host is Ubuntu 11.10 x64. I've modified those parameters in the Tomcat server.xml : <Connector port="8080" protocol="HTTP/1.1" connectionTimeout="200000" redirectPort="8443" acceptCount="2000" maxThreads="150" minSpareThreads="50" /> The application executed on the server takes around 300ms. This app is running well until a certain amount of concurrent connections like those one : ab -n 500 -c 150 http://xx.xx.xx.xx:8080/myapp/ ab -n 1000 -c 50 http://xx.xx.xx.xx:8080/myapp/ siege -b -c 100 -r 20 http://xx.xx.xx.xx:8080/myapp/ A lot of socket connection timed out happens and this completly overload the host processor (but the CPU load inside the VM is normal). Doing an htop on the host, i can see that the Virtualbox processus is running under 300% CPU and never come down even after the load test is finished. (I've allocated 4 processors to the VM, if I allocate only one processor, CPU load goes under 100%). Restarting Tomcat don't do anything, i'm forced to restart the whole VM. I've tryed to launch those ab/siege commands locally on the VM and everything goes well. I first thought it was related to a linux network limit as explained here: Running some benchmarks using ab, and tomcat starts to really slow down So I've modified those TCP parameters : echo 15 > /proc/sys/net/ipv4/tcp_fin_timeout echo 30 > /proc/sys/net/ipv4/tcp_keepalive_intvl echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse It seems to be better, but it continues to overload the host CPU and output socket connections time out at a certain amount of concurrent connections. I'm wondering if this is not related to how Virtualbox handles external concurrent connections.

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  • jquery change load get url

    - by john morris
    Ok so I have a php page with data dynamically outputs depending on a $_GET variable ['file']. I have another page (index.php) which has a jQuery script that uses the load() function to load the php page. I have a list of links and when you click on one, it needs to change the $_GET variable to load, then refresh the load() jQuery variable. Heres a snippet: $("#remote-files").load("data.php?file=wat.txt"); $(".link1").mousedown(function() { $("#remote-files").load("data.php?file=link1.txt"); }); As you can see it loads the data into a div with the ID of remote-files. Is there a better way to do this, like update the page with the new get variable instead of redefining a new load function?

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  • Load-balancing between a Procurve switch and a server

    - by vlad
    Hello I've been searching around the web for this problem i've been having. It's similar in a way to this question: How exactly & specifically does layer 3 LACP destination address hashing work? My setup is as follows: I have a central switch, a Procurve 2510G-24, image version Y.11.16. It's the center of a star topology, there are four switches connected to it via a single gigabit link. Those switches service the users. On the central switch, I have a server with two gigabit interfaces that I want to bond together in order to achieve higher throughput, and two other servers that have single gigabit connections to the switch. The topology looks as follows: sw1 sw2 sw3 sw4 | | | | --------------------- | sw0 | --------------------- || | | srv1 srv2 srv3 The servers were running FreeBSD 8.1. On srv1 I set up a lagg interface using the lacp protocol, and on the switch I set up a trunk for the two ports using lacp as well. The switch showed that the server was a lacp partner, I could ping the server from another computer, and the server could ping other computers. If I unplugged one of the cables, the connection would keep working, so everything looked fine. Until I tested throughput. There was only one link used between srv1 and sw0. All testing was conducted with iperf, and load distribution was checked with systat -ifstat. I was looking to test the load balancing for both receive and send operations, as I want this server to be a file server. There were therefore two scenarios: iperf -s on srv1 and iperf -c on the other servers iperf -s on the other servers and iperf -c on srv1 connected to all the other servers. Every time only one link was used. If one cable was unplugged, the connections would keep going. However, once the cable was plugged back in, the load was not distributed. Each and every server is able to fill the gigabit link. In one-to-one test scenarios, iperf was reporting around 940Mbps. The CPU usage was around 20%, which means that the servers could withstand a doubling of the throughput. srv1 is a dell poweredge sc1425 with onboard intel 82541GI nics (em driver on freebsd). After troubleshooting a previous problem with vlan tagging on top of a lagg interface, it turned out that the em could not support this. So I figured that maybe something else is wrong with the em drivers and / or lagg stack, so I started up backtrack 4r2 on this same server. So srv1 now uses linux kernel 2.6.35.8. I set up a bonding interface bond0. The kernel module was loaded with option mode=4 in order to get lacp. The switch was happy with the link, I could ping to and from the server. I could even put vlans on top of the bonding interface. However, only half the problem was solved: if I used srv1 as a client to the other servers, iperf was reporting around 940Mbps for each connection, and bwm-ng showed, of course, a nice distribution of the load between the two nics; if I run the iperf server on srv1 and tried to connect with the other servers, there was no load balancing. I thought that maybe I was out of luck and the hashes for the two mac addresses of the clients were the same, so I brought in two new servers and tested with the four of them at the same time, and still nothing changed. I tried disabling and reenabling one of the links, and all that happened was the traffic switched from one link to the other and back to the first again. I also tried setting the trunk to "plain trunk mode" on the switch, and experimented with other bonding modes (roundrobin, xor, alb, tlb) but I never saw any traffic distribution. One interesting thing, though: one of the four switches is a Cisco 2950, image version 12.1(22)EA7. It has 48 10/100 ports and 2 gigabit uplinks. I have a server (call it srv4) with a 4 channel trunk connected to it (4x100), FreeBSD 8.0 release. The switch is connected to sw0 via gigabit. If I set up an iperf server on one of the servers connected to sw0 and a client on srv4, ALL 4 links are used, and iperf reports around 330Mbps. systat -ifstat shows all four interfaces are used. The cisco port-channel uses src-mac to balance the load. The HP should use both the source and destination according to the manual, so it should work as well. Could this mean there is some bug in the HP firmware? Am I doing something wrong?

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  • Load balancing Apache on a budget?

    - by Industrial
    Hi everyone, I am trying to get my head around the concept of load balancing to ensure availability and redundancy to keep users happy when things go wrong, rather than load balancing for the sake of offering blistering speed to millions of users. We're on a budget and trying to stick to the stuff where there's plenty of knowledge available, so running Apache on Ubuntu VPS's seems like the strategy until some famous search engine acquire us (Saturday irony included, please note). At least to me, it's a complete jungle of different solutions available. Apaches own mod_proxy & HAproxy are two that we found by a quick google search, but having zero experience of load balancing, I have no idea of what would be appropriate for our situation, or what we would look after while choosing a solution to solve our availability concerns. What is the best option for us? What should we do to get availability high whilst staying inside our budgets?

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  • High server load - [jbd2/md1-8] using 99.99% IO

    - by Alex
    I've been having spike in load over the last week. This usually occurs once or twice a day. I've managed to identify from iotop that [jbd2/md1-8] is using 99.99 % IO. During the high load times there is no high traffic to the server. Server specs are: AMD Opteron 8 core 16 GB RAM 2x2.000 GB 7.200 RPM HDD Software Raid 1 Cloudlinux + Cpanel Mysql is properly tuned Apart from the spikes, the load usually is around 0.80 at most. I've searched around but can't find what [jbd2/md1-8] does exactly. Has anyone had this problem or does anyone know a possible solution? Thank you. UPDATE: TIME TID PRIO USER DISK READ DISK WRITE SWAPIN IO COMMAND 16:05:36 399 be/3 root 0.00 B/s 38.76 K/s 0.00 % 99.99 % [jbd2/md1-8]

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