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bio website comerford.cc
location Ireland
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I currently work for MongoDB, Inc. and have a background in operations, networking and system administration. You can find me in all the usual places, but probably the most useful and relevant are listed below:

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Dec
27
answered Mongodump segmentation fault when dumping all dbs
Dec
5
answered mongo server does not start on Centos 6.4
Dec
3
comment How to calculate the required EBS PIOPS for our mongo server?
You didn't mention the instance size but I would expect single volumes to be able to do significantly more than 25 IOPS a piece (with 4 total you get the 100 figure I mentioned) - if you were seeing IOWait, high queues (and you don't seem to be) then I would expect a significant improvement. Without obvious IOPS related stress, the biggest improvement you will probably see is a reduction in peak latency (PIOPS performance is more predictable). You may get more bang for your buck getting more RAM so MongoDB can fit more data into memory and hit disk less often (depends on your usage pattern)
Dec
3
answered MongoDB Balancer
Dec
3
answered How to calculate the required EBS PIOPS for our mongo server?
Nov
26
comment Is it safe to snapshot an mdadm RAID with only xfs_freeze?
As long as the snapshot is point-in-time guaranteed you do not have to stop MongoDB (as long as the journal is included in the snapshot). Of course, that's independent of whether the snapshot itself is consistent from a data perspective across the volumes without freezing the data itself.
Nov
14
comment Spawning mongod process using sudo yields two separate mongod processes
I think the nature of the processes is answered below, but I will say this: do not start MongoDB as root, do not use sudo to run MongoDB - or any database for that matter - it is a bad, bad idea. If you switch to another user, as you should, you will have to manually fix the ownership on the various data files before the new user will be able to successfully start.
Nov
14
revised Login authentication vanished from MongoDB install
added follow up from comments as part of the answer
Nov
13
comment Login authentication vanished from MongoDB install
The only way I can think of for that to happen (besides someone/something getting access and modifying things) is for your instance to have been restarted without authentication enabled (it is off by default). You should verify what options the mongod is running with and that your admin users and database users are in fact still present.
Nov
13
answered Login authentication vanished from MongoDB install
Nov
5
answered Changing MongoDB Oplog size
Oct
24
awarded  Notable Question
Sep
19
answered Query related to production environment
Sep
19
revised Query related to production environment
Terms were slightly off, mongoose is an ODM, mongos is the router process, also fixed up some sentence structure
Sep
17
comment Very high disk IO on Mongodb Config servers
No, the change is actually in the shared connection code for any mongod/mongos (as a client) making a connection to the config server (it's a special type of connection), so no need to run the mongos with quiet.
Sep
17
revised Very high disk IO on Mongodb Config servers
added a note about the client based aspect of the fix
Sep
17
comment Very high disk IO on Mongodb Config servers
It's worth noting that the mongod's (the primaries) also write to the config servers, though less often, so worth looking at upgrading those to 2.4.5+ also. There are a couple of other things to check too - have a look at the config.changelog collection to get an idea of activity on your cluster - it's a 10MB capped collection that will show you the activity - in particular migrates will cause writes from the primaries.
Sep
17
comment Very high disk IO on Mongodb Config servers
Yes, the relevant change is actually (somewhat counter-intuitively) on the client side (the mongos) which is what decides how the writes are done on the config servers (see: github.com/mongodb/mongo/commit/…), hence you have to make sure all the mongos processes are on 2.4.5+ to resolve the issues.
Sep
16
answered Very high disk IO on Mongodb Config servers
Sep
13
answered Can I use MongoDB with Amazon EC2 small instance?