First, I tried to find any client of ours with a track record like this and have been unsuccessful. I personally have looked at every single customer case that’s every come in (there are about 1600 of them) and cannot match this story to any of them. I am confused as to the origin here, so answers cannot be complete in some cases.
Some comments below, but the most important thing I wanted to say is if you have an issue with MongoDB please reach out so that we can help. https://groups.google.com/group/mongodb-user is the support forum, or try the IRC channel.
> 1. MongoDB issues writes in unsafe ways by default in order to win benchmarks
The reason for this has absolutely nothing to do with benchmarks, and everything to do with the original API design and what we were trying to do with it. To be fair, the uses of MongoDB have shifted a great deal since then, so perhaps the defaults could change.
The philosophy is to give the driver and the user fine grained control over acknowledgement of write completions. Not all writes are created equal, and it makes sense to be able to check on writes in different ways. For example with replica sets, you can do things like “don’t acknowledge this write until its on nodes in at least 2 data centers.”
> 2. MongoDB can lose data in many startling ways
> 1. They just disappeared sometimes. Cause unknown.
There has never been a case of a record disappearing that we either have not been able to trace to a bug that was fixed immediately, or other environmental issues. If you can link to a case number, we can at least try to understand or explain what happened. Clearly a case like this would be incredibly serious, and if this did happen to you I hope you told us and if you did, we were able to understand and fix immediately.
> 2. Recovery on corrupt database was not successful, pre transaction log.
This is expected, repairing was generally meant for single servers, which itself is not recommended without journaling. If a secondary crashes without journaling, you should resync it from the primary. As an FYI, journaling is the default and almost always used in v2.0.
> 3. Replication between master and slave had gaps in the oplogs, causing slaves to be missing records the master had. Yes, there is no checksum, and yes, the replication status had the slaves current
Do you have the case number? I do not see a case where this happened, but if true would obviously be a critical bug.
> 4. Replication just stops sometimes, without error. Monitor
> your replication status!
If you mean that an error condition can occur without issuing errors to a client, then yes, this is possible. If you want verification that replication is working at write time, you can do it with w=2 getLastError parameter.
> 3. MongoDB requires a global write lock to issue any write
> Under a write-heavy load, this will kill you. If you run a blog, you maybe don't care b/c your R:W ratio is so high.
The read/write lock is definitely an issue, but a lot of progress made and more to come. 2.0 introduced better yielding, reducing the scenarios where locks are held through slow IO operations. 2.2 will continue the yielding improvements and introduce finer grained concurrency.
> 4. MongoDB's sharding doesn't work that well under load
> Adding a shard under heavy load is a nightmare. Mongo either moves chunks between shards so quickly it DOSes the production traffic, or refuses to more chunks altogether.
Once a system is at or exceeding its capacity, moving data off is of course going to be hard. I talk about this in every single presentation I’ve ever given about sharding: do no wait too long to add capacity. If you try to add capacity to a system at 100% utilization, it is not going to work.
> 5. mongos is unreliable
> The mongod/config server/mongos architecture is actually pretty reasonable and clever. Unfortunately, mongos is complete garbage. Under load, it crashed anywhere from every few hours to every few days. Restart supervision didn't always help b/c sometimes it would throw some assertion that would bail out a critical thread, but the process would stay running. Double fail.
I know of no such critical thread, can you send more details?
> 6. MongoDB actually once deleted the entire dataset
> MongoDB, 1.6, in replica set configuration, would sometimes determine the wrong node (often an empty node) was the freshest copy of the data available. It would then DELETE ALL THE DATA ON THE REPLICA (which may have been the 700GB of good data)
> They fixed this in 1.8, thank god.
Cannot find any relevant client issue, case nor commit. Can you please send something that we can look at?
> 7. Things were shipped that should have never been shipped
> Things with known, embarrassing bugs that could cause data problems were in "stable" releases--and often we weren't told about these issues until after they bit us, and then only b/c we had a super duper crazy platinum support contract with 10gen.
There is no crazy platinum contract and every issue we every find is put into the public jira. Every fix we make is public. Fixes have cases which are public. Without specifics, this is incredibly hard to discuss. When we do fix bugs we will try to get to users as fast as possible.
> 8. Replication was lackluster on busy servers
This simply sounds like a case of an overloaded server. I mentioned before, but if you want guaranteed replication, use w=2 form of getLastError.
> But, the real problem:
> 1. Don't lose data, be very deterministic with data
> 2. Employ practices to stay available
> 3. Multi-node scalability
> 4. Minimize latency at 99% and 95%
> 5. Raw req/s per resource
> 10gen's order seems to be, #5, then everything else in some order. #1 ain't in the top 3.
This is simply not true. Look at commits, look at what fixes we have made when. We have never shipped a release with a secret bug or anything remotely close to that and then secretly told certain clients. To be honest, if we were focused on raw req/s we would fix some of the code paths that waste a ton of cpu cycles. If we really cared about benchmark performance over anything else we would have dealt with the locking issues earlier so multi-threaded benchmarks would be better. (Even the most naive user benchmarks are usually multi-threaded.)
MongoDB is still a new product, there are definitely rough edges, and a seemingly infinite list of things to do.
If you want to come talk to the MongoDB team, both our offices hold open office hours where you can come and talk to the actual development teams. We try to be incredibly open, so please come and get to know us.
Although we don't yet have a fixed office hours schedule, we typically hold them every 2 weeks. The exact dates are announced via the local MongoDB Meetup Group°; we always hold the hours at "Look Mum No Hands" on Old Street.
At least one (and often several) of our Engineers make themselves available during this time to answer any questions and assist with MongoDB problems.
MongoDB simply gets better in any version and it is indeed a reliable platform, at least as human beings (employees) are.
I envy how all your (potential) customers are from California.
It might be helpful for 10gen to put together a short doc on what to watch out for evaluators.
I don't think a short doc is of any help for evaluators. You shouldn't be basing your decision on 400 words and some bullet points. If you're serious about your datastore then you should treat it seriously.
So prove you were the one who wrote the account in pastebin.
"Maybe i already work for Fox News"
"and i am the original owner"
"based on the FUD i'm spreading"
"Yes, i am a troll"
"And i think everyone who truly"
It's a different person.
nomoremongo posted the comment at 2011-11-06T03:43:48Z: http://news.ycombinator.com/item?id=3201772
nmongo posted the story at 2011-11-06T07:05:13Z: http://news.ycombinator.com/item?id=3202081
Hype, fud, fact and misinformation are all part of determining which technologies succeed and which fail.
Many of HN readers have been through 2 or 3 of those cycles and have well developed instincts for spotting BS and verifying technologies.
In other world all you've really demonstrated here is you're a bit of a dick.
You are joking again?
Now please go back to digg/reddit/4chan and tout this fine accomplishment where that's accepted.
Kudos to Eliot for coming on and answering your phony accusations. I feel sorry for him though as he has obviously spent a great deal of time in responding, when he could have been doing other important things, like fixing urgent bugs. As others have pointed out, this is the mark of a company who take very good care of their customers. Customer service is what differentiates chiefs from cowboys.
HN is an important community resource, especially for people with little startup / dev experience. I would urge you to think next time before being so irresponsible.
We use mongodb extensively, but I get the hipster feeling also, mostly because they hold office hours at Look Mum No Hands in Old Street, which is ultra proto-hipster.
nmongo's karma: 678
Account created 1 day ago.
Hacker News used to be a place where serious and somewhat time poor programmers gather to exchange ideas and learn from one another in good faith.
We are certainly not here to listen to some dumbfuck spread misinformation.
You should have known better.
Consider joining Fox News. But I'm not sure if they'll stoop this low.
There's also a couple of anecdotes of MongoDB supposedly failing in various ways in the author's experience. Are you saying those were fake?
Just because you submitted the document here does not mean you wrote it. Pastebin logs the document as being submitted on 5th Nov. http://pastebin.com/FD3xe6Jt
I don't buy it. I don't think nmongo wrote the doc on pastebin. Maybe I'm overrating my character-detection abilities, but it didn't smell like it was written by some immature time-wasting kid.
edit: I use mongo in prod; very much a student of the "right tool for the job" school. Not trying to add or subtract weight from the original text; ambivalence reigns supreme regarding internet nosql battles. Just saying that my possibly unreliable circuits detect quite a gulf between the original document and the OP's hysterical, caps-lock-engaged cry for attention here.
It is plausible that someone guessed the password of nmongo's throwaway account, quickly changed that password, and then started posting the whole thing was a hoax.