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
-
Do internal links from non-indexed pages matter?
Hi everybody! Here's my question. After a site migration, a client has seen a big drop in rankings. We're trying to narrow down the issue. It seems that they have lost around 15,000 links following the switch, but these came from pages that were blocked in the robots.txt file. I was wondering if there was any research that has been done on the impact of internal links from no-indexed pages. Would be great to hear your thoughts! Sam
Intermediate & Advanced SEO | | Blink-SEO0 -
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 -
De-indexing product "quick view" pages
Hi there, The e-commerce website I am working on seems to index all of the "quick view" pages (which normally occur as iframes on the category page) as their own unique pages, creating thousands of duplicate pages / overly-dynamic URLs. Each indexed "quick view" page has the following URL structure: www.mydomain.com/catalog/includes/inc_productquickview.jsp?prodId=89514&catgId=cat140142&KeepThis=true&TB_iframe=true&height=475&width=700 where the only thing that changes is the product ID and category number. Would using "disallow" in Robots.txt be the best way to de-indexing all of these URLs? If so, could someone help me identify how to best structure this disallow statement? Would it be: Disallow: /catalog/includes/inc_productquickview.jsp?prodID=* Thanks for your help.
Intermediate & Advanced SEO | | FPD_NYC0 -
Can too many "noindex" pages compared to "index" pages be a problem?
Hello, I have a question for you: our website virtualsheetmusic.com includes thousands of product pages, and due to Panda penalties in the past, we have no-indexed most of the product pages hoping in a sort of recovery (not yet seen though!). So, currently we have about 4,000 "index" page compared to about 80,000 "noindex" pages. Now, we plan to add additional 100,000 new product pages from a new publisher to offer our customers more music choice, and these new pages will still be marked as "noindex, follow". At the end of the integration process, we will end up having something like 180,000 "noindex, follow" pages compared to about 4,000 "index, follow" pages. Here is my question: can this huge discrepancy between 180,000 "noindex" pages and 4,000 "index" pages be a problem? Can this kind of scenario have or cause any negative effect on our current natural SEs profile? or is this something that doesn't actually matter? Any thoughts on this issue are very welcome. Thank you! Fabrizio
Intermediate & Advanced SEO | | fablau0 -
Our login pages are being indexed by Google - How do you remove them?
Each of our login pages show up under different subdomains of our website. Currently these are accessible by Google which is a huge competitive advantage for our competitors looking for our client list. We've done a few things to try to rectify the problem: - No index/archive to each login page Robot.txt to all subdomains to block search engines gone into webmaster tools and added the subdomain of one of our bigger clients then requested to remove it from Google (This would be great to do for every subdomain but we have a LOT of clients and it would require tons of backend work to make this happen.) Other than the last option, is there something we can do that will remove subdomains from being viewed from search engines? We know the robots.txt are working since the message on search results say: "A description for this result is not available because of this site's robots.txt – learn more." But we'd like the whole link to disappear.. Any suggestions?
Intermediate & Advanced SEO | | desmond.liang1 -
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 -
Duplicate page titles Wordpress SEO/Yoast
Hi I have a Wordpress site using the Wordpress SEO plugin by Yoast. Everything appears to be fine except that on 1 Feb SEOMoz crawl suddenly picked up a bunch of errors. The errors are duplicate page titles, and these exist only for the mysite.com/page/X pages. I can't find any setting in Yoast that looks wrong or tells me how to fix this. The pages are also dynamically canonicalizing to themselves - not sure if this makes any difference although I don't know how this is happening. Does anyone know how to fix this duplicate title error? Alex
Intermediate & Advanced SEO | | alextanner0 -
Number of Indexed Pages are Continuously Going Down
I am working on online retail stores. Initially, Google have indexed 10K+ pages of my website. I have checked number of indexed page before one week and pages were 8K+. Today, number of indexed pages are 7680. I can't understand why should it happen and How can fix it? I want to index maximum pages of my website.
Intermediate & Advanced SEO | | CommercePundit0