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bio website comerford.cc
location Ireland
age 35
visits member for 2 years, 10 months
seen 2 hours ago

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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Jun
19
answered Is this normal or due to bug in mongodb?
Jun
19
answered Remove a secondary from a mongo replica set without triggering re-election?
Jun
19
answered LVM+MongoDB. Dropping in speed of backup creation
Jun
14
answered Restarting MongoDB automatically if it crashes
Jun
12
comment With 3 production nodes, why Mongodb complains about even voting nodes?
It depends on your implementation, but votes are involved when deciding where a write on your replica set has made it to. Take the w:majority concern for example - that makes sure a write hits the majority of nodes in your set (in your current example, that would be 3, but with one on delay it has to hit all current nodes). Hence, removing votes can have unintended consequences. Similar mechanisms are used in migrations (sharding). Basically I talked with the engineer that wrote the replication code fro MongoDB and her advice about changing votes was: "don't do it, it's messy" :)
Jun
11
answered With 3 production nodes, why Mongodb complains about even voting nodes?
May
30
answered Problems with running a node.js application using mongoDB on a VPS running CentOS
May
30
answered Determine which guest is running on XEN: HVM or PV guest
May
30
answered MongoDB is not using all of my system memory for working set?
May
27
answered What causes SocketException (9001) handling request in node.js app and MongoDB ReplicaSet?
May
23
answered Cannot Restart MongoDB 2.4.3 on Debian 6.0.7 (32-bit)
May
22
answered MongoDB Locking - Very, very, slow to read
May
22
answered mongodb mystery crashes with sigkill under strace
May
14
awarded  Caucus
May
14
comment Mongodb production server too slow compared to staging
you can add this as an answer (and perhaps add a bit of detail about how you identified the culprit) and accept the answer yourself once enough time has gone by - I'll upvote it - knowing that whoopsie can go nuts is important :)
Apr
30
comment mongodb mystery crashes with sigkill under strace
Any chance that this is an Amazon VM?
Apr
25
comment Strange behaviour starting process with init script
In that case, the patch I mentioned above (which essentially stops the script from using numactl) should be a valid workaround for you until we fix the root issue with the bug. Just be aware that the init script may get overwritten if you upgrade at a later date.
Apr
24
comment Strange behaviour starting process with init script
ah, then numactl is installed (detected by the init script) but I believe the Linode instances are Xen VMs so I think you are OK. If in doubt, have a look here: serverfault.com/questions/471204/…
Apr
23
comment Strange behaviour starting process with init script
I think you are hitting the bug I added to the answer, looks like a numactl related issue. If you are on a non-NUMA machine, you could take a look at the patch here: jira.mongodb.org/browse/SERVER-8774 (for a NUMA enabled machine you should make sure mongod is run with numactl).
Apr
23
revised Strange behaviour starting process with init script
added a note about the relevant bug