You have been working with a customer of a Unified VNX. The customer is storing a very large number of files in a single file system that originally was 12 TB in size. File level deduplication was turned on for this file system, using fast file compression. This resulted in a compression rate of 33%.
You expanded the file system 28 days ago. The extra capacity was used immediately to store more files, making the total size 16 TB. You then changed the file deduplication from fast to deep file compression, but kept all other settings at their defaults.
The Customer has asked you to explain why the compression rate for the file system is now 36%. They had hopes of a compression rate around 45%.
What can you tell the customer?
A. Only the new 4 TB of data is compressed, using deep compression.
B. Deduplication will first take place 30 days after last access of the file.
C. The maximum size of the file system has been met, so deduplication cannot run on the last 4 TB of files.
D. The Data Mover is too heavily utilized for the deduplication job to run.
You have implemented Block Deduplication on a pool servicing a workload with a 60:40 read/write ratio, and consisting of small random IOs. This pool contains a large amount of duplicate data. After the first few deduplication processes, you notice that host response time has increased significantly.
What could be the cause of this impact on performance?
A. A write ratio of more than 30%
B. A workload with small random IOs
C. A large amount of static data
D. A small amount of unique data
A customer used the EMC VNX AVM feature to create a number of file systems. New LUNs were recently presented to AVM as VNX disk volumes. After the first file system is created, the customer receives an error message saying that there is no more space in the Storage Pool for File.
Which Storage Pool attribute could have caused this result?
A. is_dynamic
B. is_greedy
C. default_slice_flag
D. default_stack_size
You are implementing a VNX using AVM, and you cannot create any more dvols from their remaining classic LUNs to create a stripe volume.
What could be a reason for this?
A. LUNs must have the same RAID configuration.
B. LUNs must come from the same RAID Groups.
C. LUNs must not exceed 18 TB in size.
D. LUNs must have different RAID configurations.
You are implementing a VNX using AVM, and you cannot create any more dvols from their remaining classic LUNS to create a stripe volume.
What could be a reason for this?
A. LUNs must come from different RAID Groups.
B. LUNs must have different RAID configurations.
C. LUNs must not exceed 18 TB in size.
D. LUNs must come from the same RAID Group.
A customer runs a CAD/CAM application on an VNX file system. The application is accessed by users at multiple sites. The users report degraded response during peak access periods. Performance monitoring of the file system shows a higher than expected disk queue length and a higher than expected number of unused blocks pre-fetched.
What is the likely cause of the performance issue?
A. Multi-threaded sequential reads causing random access patterns
B. Single-threaded sequential reads flooding cache
C. Multi-threaded random reads degrading per-thread performance
D. Single-threaded random reads over-utilize pre-fetching
When using AVM, when is it acceptable to stripe all dvols across the same RAID Group?
A. When using Flash drives
B. When using NL-SAS drives
C. When using SAS drives
D. It is never acceptable
You are implementing a VNX into a CIFS environment.
Which server_mount command option should you use if the file system consists of database data files?
A. uncached
B. noprefetch
C. nolock
D. cifssyncwrite
You receive a call from a customer asking why they are not getting predictable performance on their new Block pool thin LUNs that they created last week.
How could the customer obtain more predictable performance from their pool?
A. Move to thick LUNs
B. Compress the thin LUNs
C. Move to a new pool and select that the LUNs stay on lowest tier
D. Move to a new pool and select that the LUNs stay on highest tier
You receive a call from a customer asking why they are not getting optimal performance on their new Block
pool LUNs that they created last week.
How could the customer obtain more predictable performance?
A. Move to classic LUNs
B. Make sure to use thin LUNs
C. Move LUNs to a new pool and select the lowest tier
D. Move LUNs to a new pool and select the highest tier
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