Moz Q&A is closed.
After more than 13 years, and tens of thousands of questions, Moz Q&A closed on 12th December 2024. Whilst we’re not completely removing the content - many posts will still be possible to view - we have locked both new posts and new replies. More details here.
How can I prevent duplicate pages being indexed because of load balancer (hosting)?
-
The site that I am optimising has a problem with duplicate pages being indexed as a result of the load balancer (which is required and set up by the hosting company).
The load balancer passes the site through to 2 different URLs:
Some how, Google have indexed 2 of the same URLs (which I was obviously hoping they wouldn't) - the first on www and the second on www2.
The hosting is a mirror image of each other (www and www2), meaning I can't upload a robots.txt to the root of www2.domain.com disallowing all. Also, I can't add a canonical script into the website header of www2.domain.com pointing the individual URLs through to www.domain.com etc.
Any suggestions as to how I can resolve this issue would be greatly appreciated!
-
There are two ways to handle load balancing, and it appears that your hosting company / server company chose to use the DNS round-robin routing option.
According to the Wikipedia page on load balancing:
http://en.wikipedia.org/wiki/Load_balancing_(computing)"Load balancing usually involves dedicated software or hardware, such as a multilayer switch or a Domain Name System server process."
Round Robin DNS Load Balancing: Basically you use the DNS routing system to handle requests. When someone visits your site, 50% of the people are routed to www.domain.com, and 50% are routed to ww1.domain.com. Both sites contain the same identical content; it's the URLs that are slightly different. Sometimes the domains are the same; but you have different IP addresses for www.domain.com.
Advantages: you don't need a dedicated load balancing piece of software or hardware, so it's less expensive.
Disadvantages: this technique exposes the individual web servers to the end user seeing the site. You can also suffer from duplicate content penalties, too. Finally, if you are relying on the round robin DNS system for load balancing, and a DNS server or one of the Web servers goes down, there's not an easy fail-over (as many DNS records are cached).More about Round Robin DNS: http://en.wikipedia.org/wiki/Round-robin_DNS
Hardware / Software Load Balancer:
In this case, your DNS zone file tells the end user to go to one IP address when they type in www.domain.com. The hardware or software load balancer then sees the request, and then hands off the content to one of the web servers in a cluster.Advantages: No duplicate content penalty; to the end user, they just see one web server and not individual sub-domains (www.domain.com and ww1.domain.com). A load balancer can also cache specific items like a CSS page, so the load on the Web server is even more minimal.
Disadvantages: You're introducing another piece of hardware or software (i.e. more cost); this piece could also be a single point of failure into the mix. You need someone to figure out how to set this up and make sure it all works.
More on this type of Load Balancing: http://en.wikipedia.org/wiki/Load_balancing_(computing)#Internet-based_services
Load balancing can get complicated as soon as you have databases involved, but with a good design, multiple front end Web servers can talk to one single backend database server. The goal would be to cache as much content as possible as "static" elements, using caching systems like Varnish, that essentially turn database-driven pages into static, old-school HTML pages. And then only when someone needs to save something from the database (i.e. making a purchase on an eCommerce site), the system then interacts with it.
My recommendation:
(1) Move from the Round Robin Robin DNS to a hardware or software load balancer.(2) If that isn't an easy solution, implement the Round Robin DNS solution to use identical A records for each server.
For example, you might have identical entries in your DNS zone files for both DNS servers:
www.domain.com A 69.94.15.10
NS2.domain.com:
www.domain.com A 75.64.18.12This should at least eliminate your duplicate content issue, but you still do have a few disadvantages (described above). This also could lead to server issues, as the servers might be confused if they are the authoritative ones.
And if both servers are sending email, pay special attention to your SPF record, to make sure that you are allowing both IP addresses to be able to send email. (This is often overlooked.)
Hope this is helpful!
-- Jeff
Got a burning SEO question?
Subscribe to Moz Pro to gain full access to Q&A, answer questions, and ask your own.
Browse Questions
Explore more categories
-
Moz Tools
Chat with the community about the Moz tools.
-
SEO Tactics
Discuss the SEO process with fellow marketers
-
Community
Discuss industry events, jobs, and news!
-
Digital Marketing
Chat about tactics outside of SEO
-
Research & Trends
Dive into research and trends in the search industry.
-
Support
Connect on product support and feature requests.
Related Questions
-
How i can increase my page authority?
Hi, I have website and i want to increase my page authority. My website is latestdatabase.com I have making more backlinks but not good page authority so far. Please give me suggest.
Intermediate & Advanced SEO | | LatestMailingDatabase1 -
How can I avoid duplicate content for a new landing page which is the same as an old one?
Hello mozers! I have a question about duplicate content for you... One on my clients pages have been dropping in search volume for a while now, and I've discovered it's because the search term isn't as popular as it used to be. So... we need to create a new landing page using a more popular search term. The page which is losing traffic is based on the search query "Can I put a solid roof on my conservatory" this only gets 0-10 searches per month according to the keyword explorer tool. However, if we changed this to "replacing conservatory roof with solid roof" this gets up to 500 searches per month. Muuuuch better! The issue is, I don't want to close down and re-direct the old page because it's got a featured snippet and sits in position 1. So I'd like to create another page instead... however, as the two are effectively the same content, I would then land myself in a duplicate content issue. If I were to put a rel="canonical" tag in the original "can I put a solid roof...." page but say the master page is now the new one, would that get around the issue?
Intermediate & Advanced SEO | | Virginia-Girtz0 -
Can Google Bot View Links on a Wix Page?
Hi, The way Wix is configured you can't see any of the on-page links within the source code. Does anyone know if Google Bots still count the links on this page? Here is the page in question: https://www.ncresourcecenter.org/business-directory If you do think Google counts these links, can you please send me URL fetcher to prove that the links are crawlable? Thank you SO much for your help.
Intermediate & Advanced SEO | | Fiyyazp0 -
Duplicate H1 on single page for mobile and desktop
I have a responsive site and whilst this works and is liked by google from a user perspective the pages could look better on mobile. I have a wordpress site and use the Divi Builder with elegant themes and have developed a separate page header for mobile that uses a manipulated background image and smaller H1 font size. When crawling the site two H1s can be detected on the same page - they are exactly the same words and only one will show according to device. However, I need to know if this will cause me a problem with google and SEO. As the mobile changes are not just font size but also adaptations to some visual elements it is not something I can simply alter in the CSS. Would appreciate some input as to whether this is a problem or not
Intermediate & Advanced SEO | | Cells4Life0 -
If Robots.txt have blocked an Image (Image URL) but the other page which can be indexed has this image, how is the image treated?
Hi MOZers, This probably is a dumb question but I have a case where the robots.tags has an image url blocked but this image is used on a page (lets call it Page A) which can be indexed. If the image on Page A has an Alt tags, then how is this information digested by crawlers? A) would Google totally ignore the image and the ALT tags information? OR B) Google would consider the ALT tags information? I am asking this because all the images on the website are blocked by robots.txt at the moment but I would really like website crawlers to crawl the alt tags information. Chances are that I will ask the webmaster to allow indexing of images too but I would like to understand what's happening currently. Looking forward to all your responses 🙂 Malika
Intermediate & Advanced SEO | | Malika11 -
Google indexed wrong pages of my website.
When I google site:www.ayurjeewan.com, after 8 pages, google shows Slider and shop pages. Which I don't want to be indexed. How can I get rid of these pages?
Intermediate & Advanced SEO | | bondhoward0 -
Links from non-indexed pages
Whilst looking for link opportunities, I have noticed that the website has a few profiles from suppliers or accredited organisations. However, a search form is required to access these pages and when I type cache:"webpage.com" the page is showing up as non-indexed. These are good websites, not spammy directory sites, but is it worth trying to get Google to index the pages? If so, what is the best method to use?
Intermediate & Advanced SEO | | maxweb0 -
Artist Bios on Multiple Pages: Duplicate Content or not?
I am currently working on an eComm site for a company that sells art prints. On each print's page, there is a bio about the artist followed by a couple of paragraphs about the print. My concern is that some artists have hundreds of prints on this site, and the bio is reprinted on every page,which makes sense from a usability standpoint, but I am concerned that it will trigger a duplicate content penalty from Google. Some people are trying to convince me that Google won't penalize for this content, since the intent is not to game the SERPs. However, I'm not confident that this isn't being penalized already, or that it won't be in the near future. Because it is just a section of text that is duplicated, but the rest of the text on each page is original, I can't use the rel=canonical tag. I've thought about putting each artist bio into a graphic, but that is a huge undertaking, and not the most elegant solution. Could I put the bio on a separate page with only the artist's info and then place that data on each print page using an <iframe>and then put a noindex,nofollow in the robots.txt file?</p> <p>Is there a better solution? Is this effort even necessary?</p> <p>Thoughts?</p></iframe>
Intermediate & Advanced SEO | | sbaylor0