sepin4
Joined 8 years ago
Joined 8 years ago
Postgre clusters can be configured in similar fashion.
I'm not saying that Mongo doesn't have it's strengths. However using the full potential of your environment requires much more planing and has a lot more pitfalls.
I was particularly discussing the implications on what the relative immutability of the shard key has on the data distribution and that it is not that easy to change.
If I want to gain a relative 100% increase in concurrent read/write access and transparent session failover to my application I have to procure two servers(with roughly the same performance lets put it at rawPerf=1.0 for simplicity) and a SAN/NAS with SCSI HBA and that would be it. All the necessary components will be running on those two servers and the application will have access to almost all capabilities of a single instance with a roughly twice the performance and fault tolerance. To do that in Mongo, I would have to procure 2 replica sets with 3 instances each(bare minimum to get the fault tolerance and not use arbiters which according to Mongo University is a bad idea) for the actual data and another RS for the configuration meta-data, which is another 3 instances. I will also need instances where I can run my "mongos" to route/consolidate my requests and to have fault tolerance I will need at least two of those. Now to do a break down of the different instances. From the two replica sets for data, I can use only 2 of the instances for writes and the remaining four only for consistent reads and that is only with the appropriate write concern. And while I have two instances for writes I am not guaranteed to get a consistent increase in write operations unless the data is at least somewhat evenly distributed. I will need six rawPerf 0.5 servers(assuming 0.5 rawPerf is capable to handle roughly half the data), that is a total of 3.0 so far. The configuration RS while not as demanding as the actual data RS will still require resources so I count it as roughly between 0.5-1.0 total for all three instances. And finally I have the "mongos" instances which although will not need disk space will need some CPU and the same amount of RAM as a regular instance in case the queries and not optimized, so I will have to give it 0.5 per instance. And the total amount of resources comes to 3.0+0.5+1.0=4.5. On the other hand with the Oracle RAC I would've needed 2.0.
As for the schema flexibility, from the Mongo documentation I take it that once the shard key is created it can't be changed arbitrarily. It can only be further fine-grained by adding more keys to it, however this is available from version 4.4. In order to change it cardinally, I would have to recreate the collection.
I'm sure you are well aware of all this, however I'm just stating my experience with MongoDB so far.
Also, this could have been resolved if this was reported in timely manner, not years after. She is a victim, however her followup actions are neither correct nor proper.
The cool thing is you can make it part of the interior. I have 3 panels hanging from the ceiling, 1 painting and one mirror. They can be integrated into hanging or floating ceilings and usually have standard dimensions. You have to be aware, that most panels do not have thermostat. They have only one operating mode - On. In order to regulate them, you have to put a thermostat on the electrical line before it(essentially a smart switch). There are thermostats for wall integration. I use those, the cables are hidden in the wall and the actual thermostat is mobile so it can measure temperature at any location in the room. There are also thermostats which are plugged directly on electrical sockets for more integration out of the box. The price is comparable to any other heating solution and the consumption is a little less than air conditioner. Mine came with 5 year warranty. I just hope that they last longer, but with the exception of the painting, all the rest are easily replaceable.