First be sure to install the latest version of TokuMX on the target machines, which is currently 1.4.2. Also, for all long-running commands, you’ll want to run them in a tmux session. You can create a new tmux session with tmux new, attach to the default session with tmux attach -d, and quit a tmux Read More

Here’s a helpful script for finding the size of every table in MongoDB in MB: var collNames = db.getCollectionNames(); for (var i = 0; i < collNames.length; i++) { var coll = db.getCollection(collNames[i]); var stats = coll.stats(1024 * 1024); print(stats.ns, stats.storageSize); }

I logged into the primary member of the replica set and ran rs.status() which showed me that the replica was too stale (“error RS102 too stale to catch up”): { “_id” : 4, “name” : “55.55.55.55:27017”, “health” : 1, “state” : 3, “stateStr” : “RECOVERING”, “uptime” : 502511, “optime” : { “t” : 1340841938000, “i” Read More

You can create a MySQL backup with Percona Xtrabackup by running: $ innobackupex –user=DBUSER –password=DBUSERPASS /path/to/BACKUP-DIR/ You can then restore the backup with: $ xtrabackup –prepare –datadir=/var/lib/mysql –target-dir=/path/to/BACKUP-DIR/ $ sudo service mysql stop $ sudo mv /var/lib/mysql ~/dbbackup $ sudo mv /path/to/BACKUP-DIR /var/lib/mysql $ sudo chown -R mysql:mysql /var/lib/mysql $ sudo service mysql start $ Read More

When dealing with distributed systems, Brewer’s CAP theorem is often brought up when discussing how a system will behave in certain error conditions. The CAP theorem means that you can only have two of: consistency, availability, and partition tolerance. Here’s what you’ll be giving up for each of the three that you may sacrifice: C: Read More