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Wednesday, May 31 • 1:20pm - 1:50pm
The effects of fragmentation and capacity on Lustre Filesystem performance

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After a Lustre file system is put in production, and the usage model fluctuates with the
variability of applications and users creating and deleting files overtime, available
storage capacity tends to decrease while file system fragmentation increases. This
affects the overall performance throughput, bandwidth, compared to a pristine file
system, or a file system which is just fully populated. Seagate will discuss a study
around both capacity and fragmentation, including the methodologies, nomenclature, and tools used to study both capacity and the introduction of fragmentation at different capacity
points to analyze the overall throughput performance impact. The talk will illustrate how,
at various percentages of capacity, the largest impact is the amount of fragmentation
that exists, and not just the utilized capacity of the file system.

The overall determination is that despite some popular belief, performance impacts
can occur at very low percentage of utilization depending on patterns of utilization
and fragmentation that may be generated by a file system's overall operational
production utilization. As such modeling behaviors, RFI’s and RFP’s should be modified
to consider factors outside a pristine file system to more properly reflect real world
operational requirements for customers. Customers can thus consider the inclusion
of such factors in their solicitation for file system proposals. Vendors in turn, will
be encouraged to perform product benchmarks that are more realistic to both
fragmentation and capacity as major constraints in Lustre file system utilization for
responses to said requirements, irrespective of whether those requirements are aligned
to a more traditional Lustre on disk filesystem, LDISKFS, or for alternate technologies
such as zfs.


John Kaitschuck

Seagate CSSG

Wednesday May 31, 2017 1:20pm - 1:50pm EDT
Alumni Hall (IMU - 1st Floor) 900 E 7th St, Bloomington, IN, 47405