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jivid

jivid on Hacker News

Re:MySQL infrastructure testing automation at GitHub on Thursday July 06, 2017 @01:52PM (#14712328)
Super interesting post. Would love to read more detail about their backup and restore infrastructure.

If Tom and/or Shlomi are reading this: you mention taking multiple logical backups per day. What benefit does this bring versus just having one per day and doing a point-in-time restore using binlogs? Is this just a tradeoff between time taken for a restore and storage you're willing to dedicate to backups?

Disclaimer: I work on Facebook's MySQL backup and restore system (https://code.facebook.com/posts/1007323976059780/continuous-...)

Re:'Check Your Backups Work' Day on Wednesday February 01, 2017 @06:00AM (#13539787)
Author here.

We use it because it works well for us. We've put a lot of work into making MySQL scale for us to the point where it's a very well supported system and one of the main choices for a lot of storage decisions.

We even use MySQL as a queue for Facebook Messenger. More details about this:

https://www.youtube.com/watch?v=eADBCKKf8PA

https://code.facebook.com/posts/820258981365363/building-mob...

Re:Continuous MySQL backup validation: Restoring backups on Sunday October 30, 2016 @12:08PM (#12830527)
In addition to what evanelias said, a logical dump also means we can load it into a MySQL instance running a different storage engine as well. In our case, it allows us to take a mysqldump from an InnoDB instance and load it into a MyRocks instance if we wish.
Re:Continuous MySQL backup validation: Restoring backups on Sunday October 30, 2016 @12:05PM (#12830512)
Instance size varies a lot because we've got a lot of different MySQL workloads, some with very different configurations.

Remember we're backing up each database separately though, not the entire MySQL instance at once. Each database's backup is in a separate file.

Re:Continuous MySQL backup validation: Restoring backups on Friday October 28, 2016 @10:03PM (#12822233)
We run a single mysqldump with --single-transaction for each database on the server, nothing special.
Re:Continuous MySQL backup validation: Restoring backups on Friday October 28, 2016 @07:46PM (#12821721)
We take logical backups, not physical, and mysqldump is the best option for that. Having logical backups means we can do logical diffs as well (see https://youtu.be/Fe2oLZ4CWD4?t=951), and we've added table checksum support to mysqldump in our branch of MySQL (https://github.com/facebook/mysql-5.6/commit/54acbbf915935a0...)
Re:Continuous MySQL backup validation: Restoring backups on Friday October 28, 2016 @07:09PM (#12821551)
There's a few different ways to verify, a few of them involving stopping replication, like you pointed out. These can also sometimes be quite expensive, so depending on the type of verification required, the verification method can be tuned.

We also implemented table checksums inside of mysqldump, allowing us to dump out the restored data and compare checksums as well, if required. https://github.com/facebook/mysql-5.6/commit/54acbbf915935a0...

Re:Continuous MySQL backup validation: Restoring backups on Friday October 28, 2016 @05:59PM (#12821120)
> Do you diff against the same base, or create an incremental chain? How many diffs do you take in between recapturing a full image? At $DAYJOB we always take full backups into a fast in-house deduplicating store.

We always diff against the same base and have 5 days in between subsequent full dumps. The number of days just comes from a trade off between space occupied by the backups and time it takes to generate them.

> Is there no better way to handling this than polling?

There's definitely different ways to approach this, we find polling works well for us. We also use the same database for crash recovery, so doing the assignments through it serves both purposes.

> Presumably you can only get this parallelism by disabling FK integrity. Is it re-enabled in the following VERIFY stage?

I'm not sure what you mean by parallelism through disabling FK integrity. Splitting the backup into its tables means we can restore a subset of tables instead of the entire backup. This allows us to load individual tables concurrently, but also not have to wait to load a massive database if all we need is a few small tables.

Re:Microsoft Ships Python Code in 1996 (2009) on Friday July 22, 2016 @04:19AM (#12142349)
Facebook has a very extensive Python codebase as well. 21% of all backend code is Python:

https://code.facebook.com/posts/1040181199381023/python-in-p...

Re:Origami – Design prototyping app by Facebook on Thursday April 14, 2016 @04:21PM (#11500033)
It works on top of Quartz Composer, which is OSX only I believe.
Re:Listen to Wikipedia on Thursday July 30, 2015 @10:05AM (#9975016)
Those addresses are websocket servers that seem to publish wikipedia changes. The app is just subscribing to the changes by opening a websocket connection to the appropriate server.

Looking at their other repos and the addresses you linked to, looks like the project for publishing the changes is at https://github.com/hatnote/wikimon, which is in turn getting changes from an IRC feed at https://meta.wikimedia.org/wiki/Research:Data#IRC_Feeds

Re:Slack was hacked on Friday March 27, 2015 @04:27PM (#9278779)
> If you have not been explicitly informed by us in a separate communication that we detected suspicious activity involving your Slack account, we are very confident that there was no unauthorized access to any of your team data (such as messages or files)
Re:Sparklines for your shell on Sunday August 03, 2014 @01:36PM (#8128531)
This could be because Github's having issues with serving archives. See https://status.github.com/

EDIT: Should be working now

Re:Show HN: The Markdown Resume on Friday July 11, 2014 @12:26PM (#8020998)
Out of curiosity, what do you use as an alternative to Word if you do have to open something in a .doc/.docx format? Surely just saying "I don't have Word because I'm a developer" can't work in every situation?
Re:Show HN: Grasswire – an Internet newsroom curated and fact-checked ... on Friday June 27, 2014 @04:21PM (#7956103)
Instead of pausing the feed, maybe a simple 'Load X new tweets' banner at the top of the feed would do a better job? Twitter actually does exactly this when loading new tweets on the feed.
Re:Passwords in plain text on Sunday June 22, 2014 @09:10AM (#7927713)
The keypair AWS generates can only be downloaded once, at the time of instance creation. Beyond that, they expect you to be in possession of the keypair when launching another instance that uses the same keypair. If you happen to lose the file, you're basically out of luck.

So to directly address your concern, you can't download the keypair at any point in time, it's just a one time thing. To me that seems much more secure than emailing out a root password and enabling password authentication by default.

Re:Passwords in plain text on Sunday June 22, 2014 @07:21AM (#7927547)
I am a Digital Ocean customer and the only password they've ever emailed me is the root password for the server I just bought. Arguably this isn't as safe as AWS' process of making you download a kaypair and only letting you login with that. However, VPS owners should get in the habit of logging on to any server they buy and immediately disabling password auth and root login via SSH, which helps negate the root password being sent over email issue to a certain extent.
Re:Runnable – jsfiddle for everything on Monday June 02, 2014 @08:07AM (#7833032)
There does seem to be a Python option below the fold.
Re:Teenagers say goodbye to Facebook and hello to messenger apps on Sunday November 10, 2013 @10:44AM (#6706816)
Correct me if I'm wrong, but aren't Kik Cards exactly what you're looking for?
Re:Age of Internet Empires: One Map With Each Country's Favorite Website on Monday October 07, 2013 @11:05AM (#6508682)
Google would be defined as google.com (or the appropriate geo-specific domain) since this map is specifically for websites, not companies owning the most popular products .

As for what would happen if they did group by company? I'm guessing that Google would be #1 pretty much everywhere, save maybe Russia and China.

Re:iOS 7 UI Stencil for Omnigraffle on Monday October 07, 2013 @10:58AM (#6508630)
I'm a little confused by the "Main action" and "Cancel" buttons. Shouldn't the Cancel button have the red text and not the other way around?
Re:Tell HN: Startup school acceptance emails are out on Monday September 30, 2013 @09:30PM (#6473502)
I'm down to split the cost of a zipcar as well! Will be going from Lower Haight

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