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
-
My product category pages are not being indexed on google can someone help?
My website has been indexed on google and all of its pages can be found on google except for the product category pages - which are where we want our traffic heading to, so this is a big problem for us. Our website is www.skirtinguk.com And an example of a page that isn't being indexed is https://www.skirtinguk.com/product-category/mdf-skirting-board/
Intermediate & Advanced SEO | | chelseaskirtinguk0 -
How to check if the page is indexable for SEs?
Hi, I'm building the extension for Chrome, which should show me the status of the indexability of the page I'm on. So, I need to know all the methods to check if the page has the potential to be crawled and indexed by a Search Engines. I've come up with a few methods: Check the URL in robots.txt file (if it's not disallowed) Check page metas (if there are not noindex meta) Check if page is the same for unregistered users (for those pages only available for registered users of the site) Are there any more methods to check if a particular page is indexable (or not closed for indexation) by Search Engines? Thanks in advance!
Intermediate & Advanced SEO | | boostaman0 -
Google indexing pages from chrome history ?
We have pages that are not linked from site yet they are indexed in Google. It could be possible if Google got these pages from browser. Does Google takes data from chrome?
Intermediate & Advanced SEO | | vivekrathore0 -
Contextual FAQ and FAQ Page, is this duplicate content?
Hi Mozzers, On my website, I have a FAQ Page (with the questions-responses of all the themes (prices, products,...)of my website) and I would like to add some thematical faq on the pages of my website. For example : adding the faq about pricing on my pricing page,... Is this duplicate content? Thank you for your help, regards. Jonathan
Intermediate & Advanced SEO | | JonathanLeplang0 -
Do I need to re-index the page after editing URL?
Hi, I had to edit some of the URLs. But, google is still showing my old URL in search results for certain keywords, which ofc get 404. By crawling with ScremingFrog it gets me 301 'page not found' and still giving old URLs. Why is that? And do I need to re-index pages with new URLs? Is 'fetch as Google' enough to do that or any other advice? Thanks a lot, hope the topic will help to someone else too. Dusan
Intermediate & Advanced SEO | | Chemometec0 -
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 -
How long does google take to show the results in SERP once the pages are indexed ?
Hi...I am a newbie & trying to optimize the website www.peprismine.com. I have 3 questions - A little background about this : Initially, close to 150 pages were indexed by google. However, we decided to remove close to 100 URLs (as they were quite similar). After the changes, we submitted the NEW sitemap (with close to 50 pages) & google has indexed those URLs in sitemap. 1. My pages were indexed by google few days back. How long does google take to display the URL in SERP once the pages get indexed ? 2. Does google give more preference to websites with more number of pages than those with lesser number of pages to display results in SERP (I have just 50 pages). Does the NUMBER of pages really matter ? 3. Does removal / change of URLs have any negative effect on ranking ? (Many of these URLs were not shown on the 1st page) An answer from SEO experts will be highly appreciated. Thnx !
Intermediate & Advanced SEO | | PepMozBot0 -
Best possible linking on site with 100K indexed pages
Hello All, First of all I would like to thank everybody here for sharing such great knowledge with such amazing and heartfelt passion.It really is good to see. Thank you. My story / question: I recently sold a site with more than 100k pages indexed in Google. I was allowed to keep links on the site.These links being actual anchor text links on both the home page as well on the 100k news articles. On top of that, my site syndicates its rss feed (Just links and titles, no content) to this page. However, the new owner made a mess, and now the site could possibly be seen as bad linking to my site. Google tells me within webmasters that this particular site gives me more than 400K backlinks. I have NEVER received one single notice from Google that I have bad links. That first. But, I was worried that this page could have been the reason why MY site tanked as bad as it did. It's the only source linking so massive to me. Just a few days ago, I got in contact with the new site owner. And he has taken my offer to help him 'better' his site. Although getting the site up to date for him is my main purpose, since I am there, I will also put effort in to optimizing the links back to my site. My question: What would be the best to do for my 'most SEO gain' out of this? The site is a news paper type of site, catering for news within the exact niche my site is trying to rank. Difference being, his is a news site, mine is not. It is commercial. Once I fix his site, there will be regular news updates all within the niche we both are in. Regularly as in several times per day. It's news. In the niche. Should I leave my rss feed in the side bars of all the content? Should I leave an achor text link on the sidebar (on all news etc.) If so: there can be just one keyword... 407K pages linking with just 1 kw?? Should I keep it to just one link on the home page? I would love to hear what you guys think. (My domain is from 2001. Like a quality wine. However, still tanked like a submarine.) ALL SEO reports I got here are now Grade A. The site is finally fully optimized. Truly nice to have that confirmation. Now I hope someone will be able to tell me what is best to do, in order to get the most SEO gain out of this for my site. Thank you.
Intermediate & Advanced SEO | | richardo24hr0