There used to be this setting in zk. zookeeper.forceSync Using Kafka I used to set this setting to false, The reason is I had a number of clients writing offsets to zk and the disk system was always sync-ing dirty pages. The system would be super high IO wait.
I set this to false and disk usage basically dropped to 0. On Wed, Oct 21, 2015 at 1:47 PM, Ivan Kelly <[email protected]> wrote: > > > > What's your opinion on running Zookeeper with file system journaling > > disabled on an EXT4 file system? > > We need every ounce of performance out of it, and I believe given the > > Zookeeper implementation (operations are logged, majority quorum is > > required for succeeding, checkpoints are swapped only after being > complete) > > I feel that EXT4 journaling is redundant. Disabling EXT4 journaling could > > improve performance. We have 5 servers in a Zookeeper ensemble. Am I > > missing something or this should be fine? > > I would recommend against it. With ext4 journalling disabled, a server > crash will likely lose data, unless you have all write caching disabled. If > you have all write caching disabled, I'd expect to see worse performance > for all applications. It's not much safer than running in a ramdisk. > > -Ivan >
