ceph

Ceph recovery backfilling affecting production instances

Submitted by alvaro.soto on Wed, 06/14/2017 - 21:06

In any kind of distributed system you will have to choose between consistency, availability and partitioning, the CAP theorem states that in the presence of a network partition, one has to choose between consistency and availability, by default (default configurations) CEPH provides consistency and partitioning, just take in count that CEPH has many config options: ~860 in hammer, ~1100 in jewel, check this out, is jewel github co

Solve Ceph Clock Skew error

Submitted by alvaro.soto on Wed, 11/16/2016 - 01:21

Monitors can be severely affected by significant clock skews across the monitor nodes. This usually translates into weird behavior with no obvious cause. To avoid such issues, you should run a clock synchronization tool on your monitor nodes by default the monitors will allow clocks to drift up to 0.05 seconds.

This error can be seen using:

# ceph -s
# ceph health detail

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Cloning a Ceph client auth key

Submitted by alvaro.soto on Wed, 11/16/2016 - 00:54

I don't recall any reason to do this other than using the same user and auth key to authenticate in different Ceph clusters, like in a multi-backend solution, or just because things get messy when you are not using a default configuration.

Sometimes, things gets easy when we use the same user and auth key on both clusters for services to connect to, so lets see some background commands for managing users, keys and permissions:

Create new user and auth token (cinder client example):

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