3.7.0 HP StorageWorks HP Scalable NAS File Serving Software administration guide - HP Scalable NAS 3.7 for Linux (AG513-96002, October 2009)

10. Reducing the number of changes that are being made to files being replicated
will reduce the load on both source and destination systems. If the number of
changes being made cannot be reduced or predicted (say, in a home directory
environment), increasing the size of the changes will tend to make replication
more efficient in its use of network bandwidth.
11. Reducing the depth of directories being replicated will improve the performance
of replication on the destination nodes. HP does not recommend that directory
structures over 200 directories deep be defined as candidates for replication.
Deep directory structures cause replication to spend large amounts of time (CPU
and wall-clock) traversing directory trees ensuring that files have been correctly
replicated. While deep directory structures will ultimately replicate successfully,
they place a heavy load on the system.
12. If you have a very large amount of data to replicate at initial system setup (that
is, you have never replicated before and you have a large amount of data to
be replicated to sync the source and destination systems), best practice for the
initial replication startup is to manually back up the source data, transport it to
the destination system, and restore the data to the backup system before starting
replication. Even if the data is not in perfect sync, this reduces the amount of
data that must be transferred to get the source and destination systems in sync.
13. If a manual setup of the source and destination systems as suggested in item 12
above is not feasible, replication is more efficient if the source data is put into
place before replication is started.
Modify system parameters
Modifying certain system parameters will improve replication performance, especially
on limited memory systems. HP recommends adjusting these parameters on all
replication nodes (including the destination nodes).
NOTE:
On HP X5500 Storage Gateway for Linux, HP Clustered Gateway, and HP 4400
Scalable NAS systems, these parameters are set appropriately in the
SizingActions script that is run as a part of the system startup. There is no need
to modify the parameters for these systems.
The system parameters most affecting replication are the VM parameters
min_free_kbytes and vfs_cache_pressure.
• When using the replication feature it is important to monitor system virtual memory
utilization. HP recommends setting vm.min_free_kbytes to at least 5% of your
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