StorNext File System Tuning
The Metadata Controller System
StorNext File System Tuning Guide 9
However, it is critical that the MDC system have enough physical
memory available to ensure that the FSM process doesn’t get swapped
out. Otherwise, severe performance degradation and system instability
can result.
The operating system on the metadata controller must always be run in
U.S. English.
FSM Configuration File
Settings 0The following FSM configuration file settings are explained in greater
detail in the cvfs_config man page. For a sample FSM configuration file,
see Sample FSM Configuration File on page28.
The examples in the following sections are excerpted from the sample
configuration file from Sample FSM Configuration File on page 28.
Stripe Groups 0
Splitting apart data, metadata, and journal into separate stripe groups is
usually the most important performance tactic. The create, remove, and
allocate (e.g., write) operations are very sensitive to I/O latency of the
journal stripe group. Configuring a separate stripe group for journal
greatly benefits the speed of these operations because disk seek latency is
minimized. However, if create, remove, and allocate performance aren't
critical, it is okay to share a stripe group for both metadata and journal,
but be sure to set the exclusive property on the stripe group so it doesn't
get allocated for data as well. It is recommended that you assign only a
single LUN for each journal or metadata stripe group. Multiple metadata
stripe groups can be utilized to increase metadata I/O throughput
through concurrency. RAID1 mirroring is optimal for metadata and
journal storage. Utilizing the write-back caching feature of the RAID
system (as described previously) is critical to optimizing performance of
the journal and metadata stripe groups.
Example:
[stripeGroup RegularFiles]
Status UP
Exclusive No ##Non-Exclusive stripeGroup for all Files##
Read Enabled
Write Enabled
StripeBreadth 256K