FlashArray

Question 1

How many drives can fail on one RAID HA group?

Answer 1

2

Question 2

What is the minimum number of drives a FlashArray can run on?

Answer 2

5

Question 3

How many 9s of availability on a FlashArray?

Answer 3

6 9s
99.9999%

Question 4

How do you power off a FlashArray?

Answer 4

Pull the power cables

Question 5

What is the minimum version of Purity//FA required for SafeMode?

Answer 5

FlashArray SafeMode requires Purity//FA 5.3.7 or later

Question 6

What is the minimum version of Purity//FA required for ActiveCluster IP?

Answer 6

For new IP replication installs, Purity//FA 5.2.4 or greater must be installed

Question 7

What is the minimum version of Purity//FA required for ActiveCluster FC?

Answer 7

For new Fibre Channel replication installs, Purity//FA 6.1.x or greater must be installed

Question 8

What is the minimum version of Purity//FA required for ActiveDR?

Answer 8

For new installs, Purity//FA 6.0.1 or greater must be installed.

Question 9

What is VM Analytics?

Answer 9

VM Analytics offers a visual representation of the IO path from the VM all the way through to the FlashArray

Question 10

How long should data have been moved to the array before data reduction is likely to have reached expected levels?

Answer 10

~1 day for every 2TB of data migrated on to the array

Question 11

Usable capacity in TiB is typically what percentage of raw capacity in TB?

Answer 11

Between 60% - 70%

Question 12

At which version of Purity//FA did SafeMode support automatic snapshots and provide GUI based SafeMode status?

Answer 12

Purity//FA 6.2.x

Question 13

What are the benefits of the Front-End Active/Active architecture?

Answer 13

No need for advanced multi-pathing software
All devices are balanced across all ports - no ownership
No device to initiator mapping

Question 14

What are the benefits of the Back-End Active/Standby architecture?

Answer 14

No performance impact during controller failure
No tuning or balancing required to avoid over 100% in failure mode

Question 15

What is the customer value of our Front-End Active/Active and Back-End Active/Standby architecture?

Answer 15

The consumer only focuses on balancing the SAN, we do the rest
Enable technology transition to next generation without impact
NDU

Question 16

What does ARP stand for?

Answer 16

Acknowledge
Reduce
Protect

Question 17

What are the 15 architectural decisions which guide FlashArray development?

Answer 17

1) Built in Simplicity
2) Most Efficient Architecture at Scale
3) Consumer Flash (MLC)
4) Data Reduction
5) Stateless Controllers
6) Front End Active/Active and Back End Active/Standby
7) Streamlined Code Paths
8) Immutable, Usable Snapshots
9) Realistic Efficiency Metrics
10) Adaptive Flexible RAID
11) Security and Encryption: All the Data, All the Time
12) Metadata: The Secret Sauce
13) Proactive, Predictive Support
14) Non-Disruptive Everything

Question 18

What are the three key process of the Acknowledge stage?

Answer 18

Checksum
Copy to NVRAM
Acknowledge to host

Question 19

What are the three key process of the Reduce stage?

Answer 19

Pattern removal
Deduplication
Compression

Question 20

What are the three key process of the Protect stage?

Answer 20

Create RAID-HA segments
Flush writes via flash scheduler
Encrypt

Question 21

What are the key processes of FlashCare

Answer 21

Global wear levelling and refresh
Global deletion management
Integrity checking
Continuous optimisation

Question 22

What are the processes in the Read of an IO?

Answer 22

Multi-path Read
- Read from fastest path via scheduler
- Decompress
Validate and Serve
- Validate checksums

Question 23

Describe the process of a write request

Answer 23

1) WRITE_RQST to Block Driver
2) Prepare I/O Buffer (DRAM)
3) XFER_RDY
4) Data comes in via either controller
5) Mirrored to I/O Buffer in each controller
6) Primary I/O buffer duplicates block to at least two NVRAM cards
7) ACK to host, data is secured even in event of power loss

Question 24

Describe the in-line Data Reduction Steps

Answer 24

1) Identify and remove Zeros
2) Identify and remove Patterns
3) Identify and remove Duplicate Blocks
4) Compress Unique Blocks

Question 25

What size sectors does FlashArray store data?

Answer 25

512 Bytes

Question 26

Against how many 512B sectors do we initially generate a 128-bit hash?

Answer 26

8 (4KB)

Question 27

Up to what size does Purity variable block-size dedupe look for matches?

Answer 27

32K (64 x 512B sectors)

Question 28

How many DFMs in a normal size Write Group?

Answer 28

Up to 10

Question 29

How many RAID segments in a normal size Write Group?

Answer 29

6+2
6 data and 2 protection

Question 30

How many DFMs in a Wide Write Group?

Answer 30

Up to 28 or 40 for XL

Question 31

How many RAID segments in a Wide Write Group?

Answer 31

14+2
14 data and 2 protection

Question 32

What connects the two controllers within the chassis?

Answer 32

NTB
Non-Transparent Bridge, low latency PCIe connection via passive backplane