SPEED PowerMax Exam Flashcards
Which type of write operation is most efficient for the system and requires the least amount of system resources to perform?
write on a track that is already marked as write pending
Using the output of the symcfg list - v command below, how many slots are available for caching write operations?
130.2
How does a Delayed Fast Write (Sustained Write) differ from a Fast Write (Max Write)?
The fast writes are the maximum write rate measured, usually when the write pending count is very low. The delayed fast write is the rate we can sustain writes for a long time, usually at the write pending limit
Choose the correct statement about mainframe workloads as they compare to open system workloads
mainframe systems typically have a higher percentage of read hits and often require more front end resources than back end resources
The architecture of the PowerMax pools CPU resources. How are these resources allocated to specific emulations?
when the system is initialized CPU cores are allocated based on the different emulation types that are configured and other configuration considerations
on a PowerMax, a host is writing a 64KB block and the Logical Block Address is not aligned with the Cache Slot Size. What is the impact to system performance?
it may increase both cache utilization and IO to physical disk, and this could increase resource utilization and potentially impact system performance
How do you minimize the chance of misaligned IO by a host connected to a PowerMax?
using Host software, align the partition so that data begins at an offset in multiples of 128K
Under which of the following conditions is a PowerMax system said to be unbalanced?
when the average utilization of some system components is siginificantly different from that of components of the same type
On a PowerMax, how many disk operations are involved when a backend director performs an uncompressed 16K write on a RAID5 4+1 data device?
there would be 4 disk IO operations: two reads and two writes
Which statement is most accurate about how RAID protection is configured on a PowerMax system?
physical disks are logically divided into hypers and hypers are used to create RAID protected data devices (TDATs)
Which RAID protection has the least overhead for small block read operations and would provide the best system performance given the same number, type, and size of the physical disks?
All three have roughly the same small block read performacne
If a workload is spread evenly across all logical block addresses of all devices, what is the skew?
No workload skew
What is the benefit does RAID protection provide in both VMAX and PowerMax?
eliminates the disk drive as a single point of failure
What is the primary advantage of RAID-6?
Availability
A workload has a skew of 85/20. To what is this referring?
85% of the IO activity is being performed against 20% of the capacity
Which workload would be most efficient for RAID-5?
large block sequential writes
There are two choices for configuring RAID 5: 4+1 and 8+1. For the same number and size of drives, which configuration would provide the better performance for a random small block read and write application?
during normal operations there is no difference in performance
There are two choices for configuring RAID 6: 4+2 and 14+2. For the same number and size of drives, which configuration would provide the better performance for a random small block read and write application?
RAID 6 6+2 would be better as there would be more drives
You have been asked to size a PowerMax system and were told that the system needs to be able to do at least 180K IOPS and present a minimum of 300TB of storage. What other information do you need to start sizing the system?
the workload characteristics
Which object is a logical grouping of TDEVs?
storage groups
What is the best option for designing a PowerMax system for maximum availability?
mirror the production PowerMax in an SRDF/S configuration