ssh – fabric appears to start apache2 but doesn’t – Stack Overflow
fabric fail. pty=False fixes the bug
‘Copysets: Reducing the Frequency of Data Loss in Cloud Storage’ [paper]
An improved replica-selection algorithm for replicated storage systems.
We present Copyset Replication, a novel general purpose replication technique that signi?cantly reduces the frequency of data loss events. We implemented and evaluated Copyset Replication on two open source data center storage systems, HDFS and RAMCloud, and show it incurs a low overhead on all operations. Such systems require that each node’s data be scattered across several nodes for parallel data recovery and access. Copyset Replication presents a near optimal tradeoff between the number of nodes on which the data is scattered and the probability of data loss. For example, in a 5000-node RAMCloud cluster under a power outage, Copyset Replication reduces the probability of data loss from 99.99% to 0.15%. For Facebook’s HDFS cluster, it reduces the probability from 22.8% to 0.78%.
(tags: storage cloud-storage replication data reliability fault-tolerance copysets replicas data-loss)