Fibre Channel (SAN)

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Occasional Visitor
Posts: 1
Registered: ‎07-09-2015

What is the expected throughput for a 8Gbps NPIV Port

We have Multiple 8Gbps NPIV ports in our environment. Server team is complaing that they do not see expected bandwidth on the server and seeing performance issues. When I checked using portperfshow command, I could see upto 900m throughput on the port during peak hours, which is shared with 27 servers.

 

What would be the expected throughput on 8Gbps port. How do we calculate throughput?. I do not see any errors or discards on this port.

 

Frequent Contributor
Posts: 80
Registered: ‎01-28-2010

Re: What is the expected throughput for a 8Gbps NPIV Port

just a question for better understanding

 

you have one port and on this port you have 27 different (npiv) wwns?

 

If you have 8 GBit/sec FibreChannel adapters your max throughput will be 800
MByte/sec to a single LUN via a single path.ergo dual connected server 800MByte/sec per adapter

if you have 27 instances on one san port then those 27 instances share the 800MByte/sec connection.

 

about your question whats the max expected throughput on a 8 Gbps, its 8,5 gbps per port, not per instance.

 

i hope this kinda helps, but if you hope you dont believe in it.

so shoot if you have more questions.

 

 

Occasional Contributor
Posts: 7
Registered: ‎07-10-2015

Re: What is the expected throughput for a 8Gbps NPIV Port

We do not see any discards or erors on this port. But still server team says they do not see expected bandwidth. What is 900m stands for when I checked using portperfshow command. is it 900 Megabytes / s ? Is there anyway to findout utilization through CLI ? Whether the utilization of partuculat port is more than 80% or not ?

 

Frequent Contributor
Posts: 80
Registered: ‎01-28-2010

Re: What is the expected throughput for a 8Gbps NPIV Port

you activate bottleneckmon on that switch

 

bottleneckmon --enable -alert

and with the command bottleneckmon --show you can check what ports are over 80%

 

bottleneckmon is standard configured to report ports that use 80% or more port utilization over a time of 300 seconds

 

or you use BNA and check the historical data, if you have bna implmented

Occasional Contributor
Posts: 7
Registered: ‎07-10-2015

Re: What is the expected throughput for a 8Gbps NPIV Port

This is the output I am getting when using perfshow command during peak hours,

 

26 Total

=======================

slot 1: 966.9m 966.9m

26 Total

=======================

slot 1: 916.9m 916.9m

26 Total

=======================

slot 1: 913.6m 913.6m

26 Total

=======================

slot 1: 679.0m 679.0m

26 Total

=======================

slot 1: 762.8m 762.8m

26 Total

=======================

slot 1: 638.9m 638.9m

26 Total

=======================

slot 1: 949.5m 949.5m

26 Total

=======================

slot 1: 947.8m 947.8m

26 Total

=======================

slot 1: 845.7m 845.7m

26 Total

=======================

slot 1: 762.8m 762.8m

26 Total

=======================

slot 1: 856.7m 856.7m

26 Total

=======================

slot 1: 939.7m 939.7m

 

Frequent Contributor
Posts: 80
Registered: ‎01-28-2010

Re: What is the expected throughput for a 8Gbps NPIV Port

you use 27 instances on this one port, are you able to move some instances away from that host so it uses other ports? or is this the only host you can run those 27 instances

Occasional Contributor
Posts: 7
Registered: ‎07-10-2015

Re: What is the expected throughput for a 8Gbps NPIV Port

If this is an indication of real performance issue, we have to move some of the devices..This is the output I am getting when checked hte congestion. What is the expected rate on port ? 

 

From                    To                      affected secs
=============================================================
Jul 18 17:02:39         Jul 18 17:02:49         0.00%
Jul 18 17:02:29         Jul 18 17:02:39         0.00%
Jul 18 17:02:19         Jul 18 17:02:29         0.00%
Jul 18 17:02:09         Jul 18 17:02:19         0.00%
Jul 18 17:01:59         Jul 18 17:02:09         0.00%
Jul 18 17:01:49         Jul 18 17:01:59         0.00%
Jul 18 17:01:39         Jul 18 17:01:49         0.00%
Jul 18 17:01:29         Jul 18 17:01:39         0.00%
Jul 18 17:01:19         Jul 18 17:01:29         0.00%
Jul 18 17:01:09         Jul 18 17:01:19         0.00%
Jul 18 17:00:59         Jul 18 17:01:09         0.00%
Jul 18 17:00:49         Jul 18 17:00:59         0.00%
Jul 18 17:00:39         Jul 18 17:00:49         0.00%
Jul 18 17:00:29         Jul 18 17:00:39         0.00%
Jul 18 17:00:19         Jul 18 17:00:29         10.00%
Jul 18 17:00:09         Jul 18 17:00:19         20.00%
Jul 18 16:59:59         Jul 18 17:00:09         10.00%
Jul 18 16:59:49         Jul 18 16:59:59         0.00%
Jul 18 16:59:39         Jul 18 16:59:49         0.00%
Jul 18 16:59:29         Jul 18 16:59:39         0.00%
Jul 18 16:59:19         Jul 18 16:59:29         10.00%

Occasional Contributor
Posts: 7
Registered: ‎07-10-2015

Re: What is the expected throughput for a 8Gbps NPIV Port

We can move some of the instances if the port utilization is really high. But I want to make sure that before making any changes from our end.

Valued Contributor
Posts: 555
Registered: ‎03-20-2011

Re: What is the expected throughput for a 8Gbps NPIV Port

Maximum theoretical performance of the 8G port is 800 MB/s reads plus 800 MB/s writes. So 900 MB/s that you see in portperfshow is OK, but you don't know how they are split between reads and writes. You see, if that's 800 MB/s reads and 100 MB/s writes - then you've already reached the roof. To understand the ratio, you need to analyze RX and TX counters.
Occasional Contributor
Posts: 7
Registered: ‎07-10-2015

Re: What is the expected throughput for a 8Gbps NPIV Port

             Tx         Rx

======================

slot 1: 505.6m 170.8m

26

======================

slot 1: 676.0m 140.3m

26

======================

slot 1: 463.2m 95.5m

26

======================

slot 1: 401.2m 65.5m

26

======================

slot 1: 458.1m 86.5m

26

======================

slot 1: 504.3m 114.8m

26

======================

slot 1: 494.7m 95.1m

26

======================

slot 1: 441.0m 83.0m

26

======================

slot 1: 356.4m 106.5m

26

======================

slot 1: 425.6m 96.0m

26

======================

slot 1: 550.1m 135.7m

26

======================

slot 1: 407.9m 152.8m

26

======================

slot 1: 401.0m 177.1m

26

======================

slot 1: 354.3m 300.7m

26

======================

slot 1: 348.7m 124.3m

26

======================

slot 1: 508.2m 154.9m

26

======================

slot 1: 462.3m 102.4m

26

======================

slot 1: 493.1m 107.9m

26

======================

slot 1: 242.1m 106.1m

26

======================

slot 1: 277.3m 145.9m

26

======================

slot 1: 457.9m 124.8m

26

======================

slot 1: 543.4m 153.2m

26

======================

slot 1: 599.4m 145.9m

26

======================

slot 1: 457.5m 131.6m

26

======================

slot 1: 485.4m 175.7m

26

======================

slot 1: 503.4m 226.3m

26

======================

slot 1: 475.9m 113.6m

26

======================

slot 1: 206.1m 145.3m

26

======================

slot 1: 451.9m 147.6m

26

======================

slot 1: 603.6m 139.7m

26

======================

slot 1: 689.7m 137.0m

26

======================

slot 1: 462.9m 138.2m

26

======================

slot 1: 454.9m 111.5m

26

======================

slot 1: 419.5m 151.4m

26

======================

slot 1: 288.0m 120.2m

26

======================

slot 1: 342.4m 131.9m

26

======================

slot 1: 455.3m 129.8m

26

======================

slot 1: 694.9m 123.4m

26

======================

slot 1: 633.6m 109.4m

26

======================

slot 1: 533.3m 117.6m

26

======================

slot 1: 432.8m 301.4m

26

======================

slot 1: 507.9m 179.1m

26

======================

slot 1: 355.4m 132.1m

26

======================

slot 1: 525.2m 121.1m

26

======================

slot 1: 581.7m 150.1m

26

======================

slot 1: 704.4m 102.5m

26

======================

slot 1: 642.7m 119.4m

26

======================

 

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