Midrange Storage Performance Planning: System Configuration Considerations Flashcards
How are SPs configured in Unity XT?
dual SPs w/ mirrored write cache
What does each Unity XT SP have?
both contain primary cached data for its own LUNs and secondary copy of the cache for its peer SP
What are CMI channels used for in Unity XT?
for inter-SP communications
How are CMI channels configured in Unity XT 380?
single CMI channel per SP
How are CMI channels configured in Unity XT 480 or higher?
two CMI channels per SP
What is the CPU in the Unity 380 XT?
single socket Intel 6 cores
What is the CPU in the Unity 480 XT or higher?
dual socket Intel between 16 and 32 cores
What does the bus do in a Unity XT?
controls how much write bandwidth can be ingested by the system
What are CMI channels mostly used for in Unity?
mirroring writes between SPs
passing data from nonpreferred to preferred paths
What is the maximum write bandwidth on Unity XT 380?
5.5GB/s - lower than 480 since it only has single CMI channel
What is the maximum write bandwidth on Unity XT 480 or higher?
9.3GB/s
What is typically the bottleneck for write bandwidth on Unity?
the onboard SAS chip (if SAS IO Module isn’t installed)
What does the Unity XT architecture do for CPU utilization?
results in nonlinear CPU utilization as workload scales
What can Unity models with more CPU power do?
deliver higher performance reducing the IOPS bottleneck
What can Unity models with larger buffer caches per SP do?
improve certain Unity features like data reduction
What does buffer cache assist with in Unity?
helps cache metadata IOs
reduces backend reads/writes
why does buffer cache affect data reduction on Unity?
enough memory and CPU cycles are important to conduct the reduction algorithms
What is the relationship between resource utilization and performance?
when utilization is below the max level average response time is better
Why is it better to be underutilized on storage platforms?
system can handle activity bursts without becoming overloaded
performance can be maintained during hardware failure scenarios
What is best for SP utilization in Unity?
want it roughly equivalent across both SPs
What is low utilization considered on Unity SPs?
below 50%
system can accept extra workload
single SP should be able to service whole workload and maintain IOPS/response time
data reduction can be enabled
snapshots/replication can be enabled
What is normal utilization considered on Unity SPs?
50-70%
system operating normally and possible accept extra workloads
single SP should be able to service whole workload and maintain IOPS/response time
choose best candidates for data reduction and do it on only a few objects at a time
enable snapshots/replication on a few objects
What is high utilization considered on Unity SPs?
between 70-90%
system nearing saturation - carefully consider extra workloads
single SP should be able to service whole and existing IOPS but response time may slow
enable snapshots/replication on a few objects
What is extremely high utilization considered on Unity SPs?
above 90%
system saturated - cannot except new workloads
single SP not able to maintain existing IOPS
no data reduction
no snapshots
