StorEdge 6130
Hi,
We have a StorEdge 6130 connected to a SunFire V890 Server through a Qlogic 5200 fibre switch.The HBA's being used are Qlogic 2Gbps.
The problem is that the customer is doing some tests based on copying some data to the storage and finds the write speed to be 100MBps.That is below what a 2Gbps channel should provide.
The switch at the back of the storage is fixed at 2Gbps.The switch ports are fixed at 2Gbps and also the drivers for the Qlogic HBA's are installed.
The question is how can we check the speed at which the storage is actuallt transmitting data?
Also how can we find the speed at which the HBA's are working?
The point is to get the storage path to work at the desired throughput.
Any advice and pointers will be very helpful.
Thanks
# 2
Well there are a couple of things that can be checked. On the host side, you can check the throughput using iostat -Xxcn. On the array side, you can check the performance by either using the GUI, or sscs.
I believe the "list" subcommand with the "-T" switch will give some performance numbers.
This all should be run throughout all of the IO load.
Its unlikely that the Fibre Channel line speed is the problem here. It's probably the VDisk/volume configuration, combined with the IO load.
Can you define or describe the customer's test, and maybe we can help to tell you whether the customer is getting an expected data rate or not?
M-lennon, Loop vs. P-P makes no difference in the line speed behaviour of the 6130.
# 3
The mean bandwidth of the workload, in terms of demand,
is (Avg. I/O size) X (Avg. IOPS).You can expect
no more than this in Avg. bandwidth utilization.
Note the numbers you see with iostat include idle time.
To calculate the peak bandwidth you need the instantaneous
completion rate, void of idle time.
Make sure you have enough demand in the workload
(concurrent threads), and capability in the storage (I/Os
per second) to hit your numbers. i.e. if you are issuing
1 KB I/O, 90% of 2 GBit (with 10 bit encoding)
is ~ 189 K IOPS. What kind of disks are those ? :-)
Don't expect 100% efficiency, but I would hope to see
90+% or so... try with 1 MB I/O.
HTH,
Dave
# 4
Thanks Curtis, I was thinking that perhaps the link rate switch at the rear might be in the off position ( 1Gb/s ) and at that speed the switch may be configured in loop mode, decreasing performance. I mostly have experience with smaller/older fibre channel products, hence the guess.
