Salesforce.com - been told from insiders that Salesforce.com has the "...largest SQL Server installation."
The Salesforce Marketing Cloud, specifically the part of it that was ExactTarget until 2013 🙂
I'm on the SQL Server team there, and have been since 2006.
I've never personally claimed we are the largest or anything (I can't say others haven't), but we are freaking huge. While we have been using some big-data tools for analysis, SQL Server is our data engine.
Here's some ballpark numbers for just our production SQL Servers, not including hot standbys and stuff like that (I can't report specifics):
- Primary data store for our 24x7x365 always-on cloud application (we even deploy updates to our software hot - website doesn't go down, all services stay online)
- Sharded across many databases and datacenters
- Several 100+TB databases, many more at least 10TB, many PBs of live data and indexes
- Well over 5 trillion live rows (over 5 billion added daily)
- 10+ billion transactions/day
- Standard DB server: quad-socket, 2TB RAM
- Rows and rows and rows of SAN cabinets
When I joined in 2006, we had a couple SQL 2000 databases weighing in at around 2TB total. We've been blowing data in and querying it out at ever-increasing rates nonstop since then.
I will quite confidently state that SQL Server can handle massive workloads nonstop, with the proper care and feeding. Take this example from several years ago: we had one critical database that ran for over 500 days at over 5000 batches per second the entire year-and-a-half it was up. We only rebooted the server so we could upgrade it to SQL Server 2008. That's not a weird thing around here.
I will not say we've had zero downtime, but as the SQL Server tech lead in this very large data organization I've met with my counterpart tech leads for various other RDBMS systems (most of the commercial and open-source RDBMS available are in use at some capacity somewhere). We've discussed the challenges we face managing high-velocity, high-uptime, public-facing systems, and compared our approaches to addressing them within our specific tools. Ongoing issues we've had with SQL Server and our demands upon it are in no way unique to SQL Server; other vendors have no solution for those issues. A billion of anything starts to get messy. The now-CIO of the marketing cloud was in the room for those meetings, and we were just smirking and nodding at each other as the leads from different teams complained about trying to address different volume and velocity issues with their given RDBMS - because we had either solved nearly all of those problems or simply didn't have them because SQL Server provided the solution by default. I left that day-long meeting thinking "I am soooooooooooooo glad we're running SQL Server".
As part of the 2013 acquisition of ExactTarget by Salesforce, our use of SQL Server was analyzed vs. other tools such as Oracle that were in heavy use at HQ. We are a data company, and those databases are our business. If they go down, we go down, and money pours out the door. What we use, and how we use it, is subject to serious scrutiny, as billions of dollars at a publicly-traded company are at stake.
The result: last year, Salesforce and Microsoft signed a huge partnership. While much of the deal is that is our companies will work together on many cool things, at the joint press conference with Satya Nadella following the announcement, Salesforce CEO Marc Benioff (a former Oracle exec himself until he left to found Salesforce) had this to say about SQL Server:
SQL Server is something that I’ve watched grow from just an idea at Microsoft to a $6 billion business, and I’m sure will be a $10 billion business and one of the very largest and most important database products in our entire industry. And Salesforce is more committed to using SQL Server today than ever.
(Quote from RedmondMag.com: https://news.microsoft.com/speeches/satya-nadella-and-marc-benioff-microsoft-and-salesforce-com-media-briefing/ )
We have thousands of cores under license. For a man who likely has a lot of Oracle stock in his portfolio (I haven't looked), directing large piles of cash at Oracle competitors seems like something one would have to have a pretty darn good reason to do.
So I will also add that it is possible to convince a CEO that today's SQL Server is an enterprise flagship product. It's not the first time I've done it, either. BTW, there was no "please save SQL Server" effort; our numbers alone did all the work.
P.S. If you're in the U.S. Midwest and wonder how to monitor and tune monsters like this as well as your own environment, come to the Nashville SQL Saturday http://www.sqlsaturday.com/480/eventhome.aspx event in January. I'm running a day-long tuning pre-con the day before the event.