Midrange Storage Performance Planning: Back-end Connectivity

Question 1

What are the back-end SAS ports used for on Unity XT?

Answer 1

SPs use them to move data to and from the back-end drives

Question 2

How are SAS ports configured on Unity XT?

Answer 2

2 onboard 12Gb SAS ports for each SP within the DPE

Question 3

What are the maximum IOPS per port?

Answer 3

250,000 IOPS

Question 4

What is the maximum bandwidth per port?

Answer 4

2500 MB/s

Question 5

How do DAEs get connected?

Answer 5

two buses connected to mini-SAS HD ports

Question 6

How is SAS Port 0 connected?

Answer 6

internally to the SAS expander

expander connects to front facing drives

connection labeled BE0 EA0

Question 7

What is special about Unity 480 XT and higher SAS buses?

Answer 7

one internal SAS bus dedicated to the DPE

DPE drives directly accessed by the underlying SAS controllers over internal connections

DPE operates on bus 99 - separate from SAS expansion ports

read/write bandwidth higher than Unity XT 380 w/ no expansion

Question 8

What are the guidelines to follow on DAEs for Unity XT?

Answer 8

maximum number of enclosures per bus is 10

maximum number of drive slots per bus is 250

evenly distribute DAEs across back end buses

Question 9

What may be required to achieve maximum drive counts of Unity systems?

Answer 9

extra 12Gb SAS backend IO modules

Question 10

When can DAEs be added to a Unity XT?

Answer 10

while the OS is active up to the DAE and drive slot limit

DAEs/drive slots over the system limit are not allowed to come online

Question 11

What drives have the highest performance potential for Unity XT?

Answer 11

SAS Flash

Question 12

What is true about DAEs?

Answer 12

do not add performance by themselves - allow addition of more drive which can improve performance

Question 13

What is the SAS IO Module on Unity 480 XT or higher?

Answer 13

4 port 12Gb optional module for extra back-end buses

mirrored IO modules provide 8 x 4 lane or 4 x 8 lane 12Gb/s SAS ports per array for BE connection

Question 14

When is the SAS IO Module required for Unity 480 XT or higher?

Answer 14

system requires high bandwidth (greater than 10Gb/s)

system is attaching more than 19 DAEs

system contains more than 500 drives

Question 15

What’s an important con about having to add the SAS IO module to a Unity 480 XT or higher?

Answer 15

consumes an expansion slot that could otherwise be used for front end connectivity

Question 16

How is the back end cabling connected in Unity XT DAEs?

Answer 16

first DAE is cabled to DPE SAS Port 1 to begin back-end bus 1 as enclosure 0 (BE1 EA0)

rest of DAEs in bus are daisy chained where they are intertwined

Question 17

What is the embedded IO module on Powerstore 1000T-9000T?

Answer 17

embedded IO module v1 on each of the nodes

has 2 onboard 12 Gb SAS ports for attaching SAS Expansion Enclosures

base enclosure supports 2 redundant connections to expansion enclosure (Link Control Card A and B)

Question 18

What does the embedded module on Powerstore 1000T-9000T not support?

Answer 18

2 port card (100GbE QSFP)

no NVMe expansion

Question 19

What is required for NVMe expansion shelves on Powerstore?

Answer 19

module must be converted to embedded IO Module v2

Question 20

What are the cabling recommendations for connecting expansion enclosures for Powerstore?

Answer 20

use 2 meter cable to connect base to expansion

use 1 meter cable to connect expansions to each other

Question 21

What is true about back end cabling in Powerstore?

Answer 21

back-end SAS cabling is same regardless of model

Question 22

How would you connect a single expansion shelf in Powerstore?

Answer 22

cable both IO modules on the base enclosure to the LCC on the first expansion enclosure

Question 23

What is the back end NVMe cabling for Powerstore 500T?

Answer 23

the 4 Port Mezz card in each node provides two NVMe ports

ports 2 and 3 used for back end connectivity to ENS24 expansion

each base enclosure supports two redundant connections to expansion enclosure

Question 23

How would you connect two expansion shelves in Powerstore?

Answer 23

cable both IO modules on the base enclosure to the LCC on the first expansion enclosure

cable both IO modules on the base enclosure to the LCCs on the last expansion in the stack

cable expansion enclosure to expansion enclosure

Question 24

What are the cable options for Powerstore 500T NVMe back end?

Answer 24

QSFP28 to SFP28 - 25GbE passive 2 meter or 3 meter

Question 24

What is the recommendation for Powerstore back end NVMe cabling?

Answer 24

cables can’t be longer than 3 meters to avoid performance issues

2 meters cables included in purchases

Question 25

What is the back end NVMe cabling for Powerstore 1200T-9200T?

Answer 25

comes with embedded IO modules v2 in each node

has a one 2 port slot that is primarily used for 100GbE (QSFP) backend DAE connectivity

the base enclosure supports two redundant connections to the expansion enclosure

Question 26

What are the cable options for Powerstore 1200T-9200T NVMe back end?

Answer 26

QSFP28 to QSFP28 - 100GbE passive 2 meter or 3 meter