Dell EMC VxFlex Ready Node, User Manual

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Task Command
To view full parameter settings of a specific SDS (this also shows the
MDM settings) Execute the
command:
scli --
query_performan
ce_parameters
--sds_name
<NAME> --
print_all
To view full parameter settings of a specific SDC (this also shows the
MDM settings) Execute the
command:
scli --
query_performan
ce_parameters
--sdc_name
<NAME> --
print_all
Note: Refer to the "Performance Parameters" for a list containing all default and
performance profile parameters.
Caching Updates for VxFlex OS 2.x/3.x
VxFlex OS offers the following types of caching, for the purpose of enhancing system
performance:
l
RAM Read Cache (using a server’s DRAM memory)
l
DAS Cache or Cachecade (for information on DAS Cache, see VxFlex Ready Node
documentation)
l
Read Flash Cache (using SSDs or flash PCI cards)
Note: SSDs used for caching cannot be used for storage purposes.
The following table summarizes information about the caching modes provided by the
system.
Mode Description Considerations Default
Setting
RAM Read
Cache
(rmcache) Read-only
caching
performed by
server RAM. RAM Read cache, the fastest type of caching,
uses RAM that is allocated for caching. Its
size is limited to the amount of allocated
RAM.
RMCache should only be used for HDD pools. Disabled
Read Flash
Cache
(RFCache) Read-only
caching
performed by
one or more
dedicated
SSD devices
or flash PCI Read Flash Cache uses the full capacity of
SSD or flash PCI devices (up to eight) to
provide a larger footprint of read-only LRU
(least recently used) based-caching resources
for the SDS. This type of caching reacts
quickly to workload changes to speed up HDD
Read performance. Disabled
VxFlex OS performance fine-tuning
114 Dell EMC VxFlex Ready Node AMS User Guide