How to Squeeze More Efficiency Out of Your Infrastructure

Transcription

1 Technical White Paper How to Squeeze More Efficiency Out of Your Infrastructure Igor Seletskiy, Founder and CEO of CloudLinux February 200

2 Table of Contents I. Seeking a new model: A. The Current Landscape: why Linux is not optimized for the shared hosting market B. The numbers behind the business of hosting service providers The Law of One The Law of Too Much II. Just the facts: Study Methodology and Key Findings A. Methodology of study B. Just the Facts: The findings. Reliability Analysis: Tables Operational Analysis: Tables 3 2. Server Resource Utilization: 2.2 Support/ People Resource Utilization III. Finding the perfect balance with CloudLinux: A. Creating a new equilibrium B. Advantages versus other options IV. Compare and contrast the options:. Hardware options 2. Vendor Options V. Conclusion:. Making smart choices for the future 2. The Profit Factor

3 Extract Linux is an operating system (OS) that is a popular option among many types of users. It is a free OS, stable, with a high level of familiarity, solid performance and good vendor support. Its advantages have allowed it to garner of the web server market which means is it a popular choice among web hosts as well. Yet despite the obvious advantages, Linux is not fully optimized for web hosts because it was never designed specifically to address the unique set of requirements for this market. The Linux performance gap for web hosts it s all about control In a web hosting environment, a web server must support hundreds perhaps thousands of sites simultaneously while creating a well balanced, stable server environment. This is extremely difficult to achieve given the lack of solutions available to address the management of server resources down to an individual user level. This market gap remained, that is until CloudLinux.

4 I. Seeking a new model Linux is an operating system (OS) that is a popular all other Unix variations. Each option can offer differ- option among many types of users. In the web ent features and capabilities, but all options available server market, Linux has approximately today fail to deliver to web hosts the mission critical share which makes Linux an OS that many hosts technology most needed to help web hosts optimize use as well. It is a free OS, stable, enjoying a high their infrastructure. They need control over the level of familiarity, solid performance and good server's resources, as shown in Exhibit. vendor support. At its core, though, the primary A. Why Linux is not optimized for the Shared Hosting Market. benefit of Linux was its ability to provide a free, open source alternative to Unix - an OS suitable In a web hosting environment, a web server must for multi user systems to enable time sharing, support hundreds perhaps thousands of sites simulta- multi processing and complex security protocols. neously while creating a well balanced server environment. It remains a difficult challenge to optimize the Web hosts have many alternative operating number of users and also create a server that is stable systems available to them today. The options and well balanced because server resources are man- include Window, FreeBSD, Solaris, MacOSX and aged at a macro level not at a site level: Exhibit Sites cannot be managed individually 2

5 As any web host knows, not all web sites are control the CPU and IO resource needs at an individual created equal. Many sites are not well scripted or user level within the server. This control helps contain developed which can frequently cause an unex- sites that are draining the server and robbing its pected spike in demand for server resources. resources from other customers. This approach also Worse, as one or a few sites continue to drain prevents a single tenant from overloading and bring- resources, it is a challenge to identify the site ing down the server. responsible for the issue, which, if resource demands get too high, could adversely affect the Now with CloudLinux, hosting service providers can responsiveness of the server. In some cases, it can do just that. They can effectively manage the server at cause the server to crash. a per user level giving them a new level of control that can adjust to the demands resulting from the This is when the alarm bells go off both for addition of new accounts, the modification to existing system administrators who must race to find the sites with new features or scripts, the variation of the offending site and for business managers who quality of the site construct and the natural peaks and know that a down server means lots of unhappy valleys of server resource consumption. Exhibit 2 customers. Unhappy customers are also likely to provides a conceptual view of how CloudLinux intro- cancel their services. duces a new level of resource management control to The clear solution is to enable service providers to a site or user level. Standard OS CloudLinux Any website can drain resources Single website can overload server No additional security or protection High risk of downtime Resource isolation via LVE Technology Prevents resource hogging and spiking Protects all tenants from resource drains Fits more sites on one server Lowers risk, increases efficiency, and improves server performance Site 7 Site 6 Site Site 4 Site 4 Site 3 Site 3 Site 2 Site 2 Site Site = LVE s Exhibit 2 3

6 B. The numbers behind the business of web hosting Life in the real world of web hosts It s 4:00 a.m. and there is a service interruption in one of the servers. The monitoring software alerts staff who then need to be mobilized to deal with the outage, deal with probable dozens of customer issues all while trying to quickly pinpoint the site that is causing the issue. The Lower costs: More customers can be serviced efficiently on existing infrastructure More optimized servers reduces hardware footprint and thus real estate costs More efficient servers improve overall operational efficiency in server upgrades and maintenance More stable servers reduce expenses needed to support customers: issue is often hard to track because it may resolve - fewer support staff are needed to itself before any root cause analysis can be com- manage more customers pleted. - less staff time spent on fielding customer issues resulting from a This typical scenario demonstrates the challenge down server of creating the perfect balance between the load the server can efficiently handle and the number of users on the server. In many cases, the hosting service providers choose to reduce the number of accounts on a server to diminish the possibility that a server may become unstable. While this decision improves the chances that a server stays stable, it probably also means the hardware is sub optimized. The upside of finding this perfect balance can have a profound effect on the finan- Improve revenue: More customers can be serviced more efficiently increasing loyalty and customer lifetime value More efficient operations can free staff to focus on introducing newer, revenue producing opportunities However, achieving this perfect balance has eluded many web hosts all because of a few laws of numbers. cial health of hosting service providers as it can: 4

7 The Law of One whelm the server s resources again hogging In today s web host environment, the Law of CPU, IO or memory resources. of One is a primary constraint in optimizing A site introduced a new script that does not hosting infrastructure. The Law of One function properly or is badly written causing states: a single site is capable of rendering the server to respond by trying to resolve the an entire server inoperative affecting hun- script, which causes resource utilization dreds of customers at the same time. issues. These scenarios are typical and in any of these Take a closer look at how the Law of One oper- scenarios, the Service Level Agreement (SLA) is at risk ates. Today, most Linux servers in the shared along with customer loyalty. hosting market run Apache web servers. Most support CGI and FastCGI scripts written in a The Law of Too Much number of languages, such as Perl, Python, and Just as a single site can have a severe, adverse the most popular PHP. Within a typical web host affect on the server s uptime, the Law of Too server several hundreds or perhaps thousands of Much explores how too many resources are web sites with a highly diverse set of configura- spent remediating the problem caused by the tions, web applications (like blogs, shopping Law of One. carts, forums) and software set the stage for a To understand the Law of Too Much, take a look at single, badly executed site to bring down a whole how a web host would respond to a performance server. Typical causes of these outages can server incident:. Admin is notified via monitoring software include: A single user would install some piece of software that uses too much CPU, IO or memory, draining server resources, that server is down (not responding) or very slow 2. Admin would try to connect (usually via ultimately taking down the server and SSH or console) to the server. Due to server all sites. being very overloaded it might take 5-0 A site would be slashdotted, causing a sharp spike in traffic, which would over- minutes to connect server or they may have to reboot the server just to get in 3. In some instance, the system administrator 5

8 can detect the issue by running some As the provider tries to keep servers under light loads, diagnostic scripts such as ps, lsof, they often keep servers at ~ resource utilization netstat, to determine the cause of the levels to handle load spikes that inevitably come up. In load spike and shut down the offending this case, if one site suddenly uses 5 of the server website. resources, the rest of the sites only have available to 4. Sometimes the issue has no identifiable them /0th of the server a density decrease of six cause even after rebooting the server. fold. The Law of Too Much represents a reverse corre- The issue may resolve itself but is likely lation between the decrease in density caused by the to reappear perhaps within hours or Law of One and the load on the server. Nor is there an after a few days. easy alternative for customers who want to achieve These scenarios put tremendous pressure on better stability. On the surface, a hosting service administrators because the issues may not be provider may view this as an opportunity to upsell the resolved and in many cases are likely to appear customer to a dedicated or VPS server. again. But here too the Law of Too Much applies. Running a Here is where the Law of Too Much truly can have dedicated/ VPS server is often, technically or finan- catastrophic impact on performance. Take the cially too muchfor customers to manage practically. In case where a single user consumes 5 of the the Law of Too Much no one wins. server resources. This means that server density is lowered by factor of two within moments. But in real world of web hosting, it can be even worse. 6

9 II. The numbers that matter With the Law of One and the Law of Too Much tool that would: working against the hosting provider, it becomes. Select only sites in that time period that returned easier to see why existing solutions could not HTTP code 200 (the rest were counted as dormant address the issues. Evidence of the inadequacy of sites) existing server management approaches was 2. Analyze the baseline 24-hour period of the log files verified in a recent two-prong study conducted by and recorded for each site represented in the log files: CloudLinux (fielded January 200) which explored number of static requests the scope of the issue as experienced by real host- number of dynamic requests (requests to ing providers in the real world. The study was dynamic scripts) conducted using two different methodologies to static bandwidth understand the scope and impact of web hosting dynamic bandwidth (bandwidth generated infrastructure and its challenges. by scripts) popular web applications such as site runs A. Methodology behind the study 3. Select any log record for HTTP POST request was The study incorporated a combination of meth- considered to be dynamic script request odologies including a statistical analysis of server 4. Select any log record where URI included param- log activity and a survey among hosting service eters was considered dynamic script request providers. 5. Analyze log records with URIs ending with extensions such as:.php,.php3,.php4,.php5,.cgi,.pl, The CloudLinux team collected Apache access.shtml,.cfm,.rb logs from 36 servers from 8 different hosting com- The data was then organized into 4 categories by: panies. A baseline 24-hour interval was selected number of static requests, amount of static band- to analyze data. Once the parameters were estab- width, number of dynamic requests, and amount of lished for analysis, the team created a statistical dynamic bandwidth. 7

10 To analyze which popular web applications (like vbulletin, Joomla, Wordpress) different websites run, a database of web applications and their corresponding URL was created. At least 20 unique URLs per application had to be hit for the site to consider the site runs a particular web application. Additionally, a qualitative survey was conducted among 30 different web hosts which included questions related to management and performance issues that are experienced by a shared Table hosting operation. Nearly half (46.6%) of the respondents indicated B. Study Findings that they experienced downtime due to a lone site Two core areas were explored in the analysis of at least few times a month. (Table 2) the data, which focused on reliability and operational efficiency, as these tend to be key drivers to impact revenues and profits.. Reliability analysis This set of data focuses on universal incidences around reliability that occur most typically in a web hosting environment. Key Learning: A single site was consistently identified as one of top 3 leading causes for a slow or down server, accounting for 53.3% of downtime incidences followed by upgrades (scheduled or unscheduled) Table 2 at 4 and hardware failures at 3. (Table ) 8

11 Survey results indicate that while 66% of down- indicates that a very small number of sites account for time is resolved in less then 30 minutes, the a disproportionately large amount of server activity as support time to handle that downtime lasts more follows: then 2 hours in a majority (65%) of the cases. Reducing or eliminating these types of server issues causes resources to be diverted from pursuing other more profitable activities. Table 4 With servers that have more then 000 domains top site is responsible for % of the requests and 4% of the dynamic bandwidth and on servers with 300+ domains top site is responsible for 28% of dynamic v requests and 28% of dynamic bandwidth. This reverse correlation between a few sites over-consuming server resources further demonstrates the need to Table 3 create well balanced servers to avoid the risk that 2. Operational Analysis: Overwhelmingly, the unstable server performance can pose to a business. data from the analysis confirms that a key Detailed Distribution curve for log files analyzed challenge for web hosts lies in managing a small On 25% of the servers analyzed, top % of number of sites utilizing a disproportionate the sites are responsible for 5 or more of amount of resources. The opportunity exists to dynamic requests to the server. (Table 5) achieve higher density by ensuring a single site On 5 of the servers top % is responsible does not hog resources that could jeopardize the for 35%+ of the total request (the least Service Level Agreement (SLA) for other users. amount of resources used was still 9%). 2. Server Resource Utilization Analysis (Table 5) Average Distribution curve for log files analyzed: Resource utilization at a site level 9 Worse, a single site is responsible on average for 32%+ dynamic requests and at least

12 of dynamic requests. (Table 7) The results are even worse when analyzing dynamic bandwidth (bandwidth generated by scripts) as shown in Tables 8 and 9: a. On average, top % of the sites are responsible for 5 or more dynamic bandwidth. 0 Top % Dynamic Bandwidth Top Dynamic Site Requests Table Table 8 0 Top % Dynamic Requests Top Site Dynamic Bandwidth Table Table Table Top 3% Dynamic Requests 9 Table 7 Percent Active

13 It is worth noting that according to log files, Not surprisingly, /3 of the respondents approximately 4 of the sites on the servers think that customer churn can be reduced a appear to be dormant and did not get a single lot by decreasing downtime, and another /3 request within a 24-hour period (Table 0). This think that it can be reduced somewhat. further demonstrates how just a few sites can render a server vulnerable to instability. 2.2 Support/ People Resource Utilization The survey provided insights into how inefficient server performance can adversely affect the support staff resources. For 34.5% of the companies, it took -2 hours of support time to resolve the issue. For another 3% of companies - it took more then 2 hours to resolve. Table 2 Table

14 III. Finding the perfect balance with CloudLinux The data clearly demonstrates that there is an either/ or proposition often weighted in favor of potential in streamlining operations to drive choosing a sub-optimized server to ensure stability. better customer satisfaction through better CloudLinux represents a new approach for server server resource management. To date, there was management that lets web hosts create a better- virtually no technology available to allow for a balanced server that is stable but can handle more granular level of server resource allocation. This users. CloudLinux is an RPM-based Linux operating had negative consequences for businesses rang- system that is optimized for multi-tenant hosting ing from sub-optimized hardware and inefficient environments. Built on top of long-term proven Red support resource utilization. This is why Cloud- Hat Enterprise Linux, CloudLinux introduces new Linux was established. Driven to solve these innovative extensions that deliver increased server mission critical issues, CloudLinux technology stability and higher density. provides new capabilities for hosting providers and dedicated server providers. The heart of CloudLinux' innovative technology is Lightweight Virtual Environment (LVE). Unlike hyper- A. Creating a new equilibrium visor or container virtualization that create a full The goal of CloudLinux was to create new ways virtual server, an LVE isolates specific hardware for web hosts to manage site resource consump- resources such as the CPU, I/O and memory in a light- tion easily, efficiently and reliably at an individual weight container and limits these resources to a user level. It was clear that there is a trade off specific process or customer. Thus, CloudLinux between the desire to establish a stable server by achieves better separation between tenants and reducing the number of users and the goal to prevents one tenant from affecting others especially optimize the number of users on a server. It was due to a sudden peak load from a single tenant. Exhibit 3 2 = LVE s

15 LVE is technology to bring balance. resources to deliver satisfactory performance to web- LVE technology is implemented right at the core site visitors. Furthermore, a single site with many of the operating system - the Linux kernel. The requests can no longer slow down all other sites. This technology is transparent for the end user and for is the most effective way to ensure that most of the the sys administrator. It works in conjunction with sites on the server always respond well. Apache module (mod_hostinglimits) to assign Apache processes into corresponding LVE. Additionally, CloudLinux offers an optimized Apache module that automatically assigns certain websites to So, if HTTP request comes for virtual host LVE. This works transparently by giving each user their xyz.com -- mod_hostinglimits intercepts the own Lightweight Virtual Environment. Before a web- request, and switches Apache process serving site can execute any script, it is first placed in LVE and that request into LVE corresponding to the then executed under LVE constraints. Each LVE has its xyz.com domain. CPU/IO limits, so all Apache processes (as well as child processes created by them) cannot use more Once request is served, mod_hostinglimits resources then those limits. This way, for example, a removes Apache process from that LVE. site assigned of CPU will not be able to exceed its CloudLinux kernel employs fair-share scheduler limit. CloudLinux can virtually eradicate the issues that works with groups of processes instead of associated with load spikes. individual processes. The scheduler limits the share of the CPU that each group gets and ensur- By making sure that each site gets its fair share the ing that all tenants receive sufficient hardware only site that will be down is the misbehaving one. 3

16 IV. Comparing and Contrasting the Options For most hosting providers, operating systems hosting customers. Another, more significant disad- may seem to be of secondary importance or at vantage of VPS is that it has a fairly low ceiling in the least not able to have a measureable impact on number of VPSs per server. Two hundred fifty VPSs per the overall profitability of their operation. The server sounds a lot, yet, a web server with 250 web focus has been on integrating software or adding sites would be usually considered lightly loaded. It is hardware to address the complex stability for these reasons that VPS is not a practical, viable requirements. solution for web hosts. However, CloudLinux offers a step change in Another option might be clustering to provide more optimizing hardware, server resource manage- resources to tenants, Yet the configuration of cluster- ment and people resources needed to manage ing makes it as vulnerable to a resource hog as a regu- the infrastructure. Let s compare the options. lar server configuration. Alternatively, one can split up MySQL, mail, etc. onto different servers that again Strategic Factors reduces the risk as it reduces IO strain and makes In the search for a better-balanced server environ- more memory available for Apache/dynamic scripts ment, consider a few strategic alternatives: but it does not really solve the issue because it still. Virtual/Dedicated server options doesn't control resources. 2. Vendor options and support/ pricing models available With no real hardware technology options, alternate vendors may offer solutions that address the issue. Virtual/Dedicated server options There are a few ways to mitigate the impact Vendor Options outlier sites have on the performance of the The Players server. One option would be to solve this problem There is a range of vendor options in the OS market via container based virtualization (VPS). Yet, VPS today and they include: creates huge additional management issues as Red Hat Enterprise Linux, available in two variants each VPS has to be managed, updated and for servers. A base Red Hat Enterprise Linux server configured almost like any standard server. This designed for small deployments and Red Hat Enter- solution is not practical for many shared prise Linux Advanced Platform, designed for main 4

17 stream customers. Both versions are based on supported. While each of these players offers alter- common core technology and both include a nate features, they align along two tracks; enterprise comprehensive suite of open source server appli- class, paid support options or free model with free cations and virtualization capabilities. Each community provided support. While either option is option comes with a paid support option. suitable for many businesses, neither option is exactly right for a web host environment as Exhibit 4 demon- CentOS is an Enterprise-class Linux Distribution strates. CloudLinux fills the gap left between the high derived from sources freely provided to the public cost support options and the less than real time free by a prominent North American Enterprise Linux community support options. In addition, current OS vendor. CentOS is 0 binary compatible and is providers do nothing to improve the density of free, developed by a core team of developers who servers, while new technology from CloudLinux is are given support through the user community. proven to do just that. The scope of community support is broad and CloudLinux Red Hat CentOS Ubuntu $ $$$ Free Free encompasses system administrators, network Price administrators, enterprise users, managers and Support 24/7 Phone & Web core Linux contributors and users. 24/7 Phone & Web Forums & Mailing List Forums & Mailing List Updates Fast Fast Slow Fast Increases Performance YES Ubuntu is a community developed OS that is Increases Stability YES meant for the personal and very small enterprise System Management Portal YES YES Lightweight Virtual Environments YES Updates tested with Control Panels YES market. They advocate this OS as perfect for laptops, desktops and servers. Whether you use it at home, at school or at work, Ubuntu contains all the applications you ll ever need. Ubuntu is committed to remaining a free OS and is community Exhibit 4 CloudLinux is released under GNU General Public License ( Binaries of CloudLinux are provided on a per-system annual subscription basis. Subscriptions include Standard support, updates, revisions, upgrades and documentation. Regular updates provide general enhancements, new features, and additional hardware support. Revisions give access to the latest bug fixes and security errata. In addition, subscription customers can upgrade to newer versions of CloudLinux at no extra cost during the lifetime of their subscription. CloudLinux will be offered to shared hosting providers at $4 per month per license with discount plans available for shared providers. In addition, CloudLinux is available for resale as the default operating system or as an option for a dedicated service offering, by hosting providers and data centers as part of the CloudLinux Partner Program. Partner pricing will start at $8 per month for reseller licensing and discounts are available for higher volume commitments. 5

18 Conclusion: Making smart choices for the future The Profit Factor: More Uptime means More Profit It is clear that CloudLinux is committed to an open The direct ROI of CloudLinux can be expressed a few sourced, well-supported version of Linux that has ways; same amount of infrastructure can support been optimized specifically to address the unique more customers, fewer support resources can be needs of web hosts. Its open source credentials deployed to support more customers or reduction in provide new options for resource management, hardware costs can be used to serve current number server stability, and site level management all of customers. focused on delivering tangible benefits to hosting service providers. The philosophy of CloudLinux is In any of these situations, the impact of optimizing grounded in the understanding that web hosts the number of customers on a server without jeopar- and datacenters must operate at the highest dizing server performance and stability delivers a levels of efficiency and optimization. Anything positive ROI. Any improvement in density without less would undermine customer satisfaction, deterioration in server stability has a direct correlation which ultimately negatively impacts profit. to better utilization of resources. In this example: ROI of CloudLinux Density is increased by a factor of 2 Number of servers needed reduced by 5: a. 20 servers can be reduced to 0. 0 Density Increase: 2.0 Servers Needed: Number of Servers: 20 Savings per Month: $940 Cost per server (monthly): 50 Support overhead per server (monthly): 50 Increasing the density by a factor of 2 or more is the main benefit of CloudLinux. See ROI calculator at: The $2k monthly savings = $24,000 annual cost savings as demonstrated in the ROI calculation above. 6

19 The final word. The future vitality of the Internet presents exciting new revenue opportunities for hosting service providers as the Internet increasingly moves to the Cloud. This increases the need for developing a hosting infrastructure that can make full use of existing hardware to capture the profit in these evolving trends. CloudLinux acts as the building blocks for a Cloud future because it maximizes infrastructure through the synchronistic functioning between hardware and the OS. This hand in glove relationship is how smart companies choose to evolve their operations and in the process become more efficient, more responsive and more profitable. For more information, please contact: Corporate Headquarters 6 Fieldston Rd Princeton, NJ info@cloudlinux.com About CloudLinux, Inc. Founded in 2009 in Princeton, NJ, CloudLinux provides hosting companies and datacenters with the only commercially supported Linux operating system (OS) optimized for their needs. CloudLinux technology has been proven to improve density, stability and performance of shared Linux systems - improving datacenter management and scalability while helping to reduce support and operating costs. CloudLinux is a privately funded company that was developed by people with a wealth of experience in the hosting business in order to address the special needs of Service Providers. With its development team in Donetsk, Ukraine, CloudLinux combines unique expertise in the hosting and datacenter market with in-depth technical knowledge of hosting, kernel development and open source. CloudLinux was founded by Igor Seletskiy who has a 3 year successful track record of delivering innovative new products to the hosting industry including: H-Sphere, the first multi-server, commercially available control panel; FreeVPS, a container based virtualization product; CP+, a simple, single server control panel; WebShell and SiteStudio. For more information, please visit 7

20 Appendix Top Dynamic Site Requests Table Top % Dynamic Bandwidth 0 4 Table

21 0 Top % Dynamic Requests Table Top Site Dynamic Bandwidth 0 4 Table

22 0 Top 3% Dynamic Requests Table Percent Active Table