The table below lists and explains names and meanings of the DataKeeper parameters. These values are tuned by editing the /etc/default/LifeKeeper configuration file.

Parameter Name
Setting Value
Default Value
When to Apply
LKDR_CHUNK_SIZE Sets the chunk size of bitmap in kilobits. Integers 256 Creating a resource
LKDR_CONNECT_NBD_DURING_RESTORE Specifies if the NBD connection should be established when the mirror is restored (brought in-service). True or False True To improve switchover and failover performance on a cluster with multiple mirrors and multiple targets The default setting (“true”) provides the maximum data integrity as it assures that when a mirror is restored it will immediately replicate data to all targets available. To improve in-service performance (“false” setting) the NBD connections can be established during the first quickCheck interval (defined by LKCHECKINTERVAL, 120 seconds by default). While this will decrease the time required to bring the mirror in-service, it will also create an interval where data is not replicating to the targets. The performance improvement is most noticeable with multiple mirrors and multiple targets.
LKDR_SPEED_LIMIT Specifies the maximum bandwidth that a resync will ever take – this should be set high enough to allow resyncs to go at the maximum speed possible. Integers 500000 Resyncing a resource
LKDR_SPEED_LIMIT_MIN Specifies how fast the resync should be allowed to go when there is other I/O going on at the same time. As a rule of thumb, this should be set to half or less of the drive’s maximum write throughput in order to avoid starving out normal I/O activity when a resync occurs. Integers 20000 Resyncing a resource
LKDR_ASYNC_LIMIT Specifies the number of outstanding target writes that can be in flight at a given time. Increase this value for higher performance with asynchronous mirrors. Integers 4096 Creating a resource
LKDR_NO_FULL_SYNC Suppresses a full resync of newly added targets.

0: not suppress

1: suppress

As required (takes effect immediately) For detailed information, refer to “Avoiding Full Resynchronizations”.
LKDR_WAIT_FOR_PREVIOUS_SOURCE_TIMEOUT Specifies how long to wait for the previous source to join the cluster so that its bitmap can be merged. A full resync is required if replication is resumed to a target before the previous source’s bitmap is merged. This setting applies to all netraid devices; individual devices can NOT be configured with a different value.

0: do not wait

-1: wait indefinitely for the previous source to rejoin the cluster

> 0 number of seconds to wait

As required (takes effect immediately) How SIOS DataKeeper Works
NBD_NR_REQUESTS Specifies the number of outstanding I/O requests that can be in flight at a given time. Increase this value for higher mirroring performance. Integers 2048 As required (takes effect immediately)


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