Google Search Central is reminding anyone who takes servers offline for PHP patches to come back a 503 position code, which tells Google the outage is temporary.
The LinkedIn post went up Wednesday, the day PHP released emergency fixes for two critical flaws that can let attackers run code without logging in.
The article doesn’t say how lengthy a 503 can remain up. Google’s crawl charge documentation recommends against serving one for additional than one to two days, since URLs that come back it for multiple days may be dropped from the index.
What Google And Mueller Said
Google Search Central wrote:
“Serving a 503 (Service Unavailable) HTTP position code ensures already indexed URLs are preserved in Search during you work. Once you commencement serving 200 responses again, things naturally come back to normal.”
The article additionally warned against generic 404s or 200 error pages during the downtime. It connected to Google’s leaf on how HTTP position codes power its crawlers.
In a 2013 post, Google’s John Mueller wrote that returning an error leaf alongside a 200 OK position code causes Google to indicator that error content.
Mueller posted his own reminder on Bluesky before Wednesday and stated anywhere the 503 can arrive from:
“If you’re taking PHP sites downward to agenda period to agreement alongside “unplanned updates”, use HTTP 503 alternatively of letting responses period out / 404 / 500. You can do this exterior of PHP / item DNS elsewhere / CDN.”
The 2011 Google post he connected shows how to dispatch a 503 alongside PHP code, which won’t assistance whenever PHP is what’s coming down.
In a reply, a Bluesky person classified the responses roughly, from finest to worst, as 503, 500, 403, 404 and 200. Mueller called it “a fine model.”
How 503s Affect Crawling
Google’s crawl charge records lists 500, 503, and 429 responses as the way to urgently decrease crawler traffic for a abbreviated period. When Google’s crawlers hit a ample figure of URLs returning those position codes, they decrease the crawl charge throughout the complete hostname, including URLs that motionless come back content. Once the figure of errors drops, Google automatically increases the crawl charge again.
When returning a 503 or 429, you can add a Retry-After HTTP header that tells Google’s crawlers whenever to try again, either as a figure of seconds or as a date and period in UTC.
Google’s crawl charge leaf additionally warns that slower crawling method Googlebot discovers small new pages and refreshes existing ones small often. Google Ads campaigns may be canceled or paused.
When I covered comments from Google’s Gary Illyes in 2024, he stated a 503 enduring 10-15 minutes all now and afterward “is not ‘extended’ by any means, so you have to be fine.”
How Long Google Recommends Serving A 503
Google’s crawl charge leaf warns:
“We don’t propose that you do this for a lengthy duration of period (meaning, longer than 1-2 days) as it may have a negative consequence on how your location appears in Google products. For example, in the case of Search, if Googlebot observes these position codes on the identical URL for multiple days, the URL may be dropped from Google’s index.”
Google’s position codes page, the one the LinkedIn article connected to, says already indexed URLs that come back server errors are “preserved in the index, but eventually dropped.”
Google’s guide to pausing a website calls disabling a entire location an extreme measure that should lone final a extremely abbreviated time, a few days at most.
The guide additionally says not to come back a 503 for the robots.txt file, since that blocks all crawling. It adds that Google’s systems can’t refresh titles, descriptions, metadata, or organized data on a leaf that returns a 503.
Why This Matters
The 503 has to arrive from item that keeps operating during PHP is offline, specified as a CDN regulation or a impermanent server you’ve pointed DNS at. Your robots.txt document should keep responding normally so Google can motionless crawl the site. The 503 is a short-term measure, since Google’s records recommends against serving one for longer than one to two days.
Looking Ahead
Sites on PHP 8.1 or older no longer get regular authoritative updates. PHP has published constricted origin fixes for versions 7.4 through 8.1 for teams that build PHP themselves, and hosts or assistance vendors may provision their own, as Vahan Petrosyan reported for SEJ. For a closure that runs former a day or two, Google’s intermission guide points to an indexable residence leaf served alongside a 200 as a placeholder. Once the location returns 200s again, Google’s position codes leaf says crawling picks rear up gradually.
Featured Image: Tetiana Yurchenko/Shutterstock
