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Ask the Expert: Performance Calculations on Clariion/VNX
Performance calculations on the CLARiiON/VNX with RRR & Jon Klaus
Welcome to the EMC Support Community Ask the Expert conversation. This is an opportunity to learn about Performance calculations on the Clariion /VNX systems and the various considerations that must be taken into account
This discussion begins on Monday, August 13th. Get ready by bookmarking this page or signing up for email notifications.
Your hosts:
Rob Koper is working in the IT industry since 1994 and since 2004 working for Open Line Consultancy. He started with Clariion CX300 and DMX-2 and worked with all newer arrays ever since, up to current technologies like VNX 5700 and the larger DMX-4 and VMAX 20k systems. He's mainly involved in managing and migrating data to storage arrays over large Cisco and Brocade SANs that span multiple sites widely spread through the Netherlands. Since 2007 he's an active member on ECN and the Support Forums and he currently holds Proven Professional certifications like Implementation Engineer for VNX, Clariion (expert) and Symmetrix as well as Technology Architect for Clariion and Symmetrix.
Jon Klaus has been working at Open Line since 2008 as a project consultant on various storage and server virtualization projects. To prepare for these projects, an intensive one year barrage of courses on CLARiiON and Celerra has yielded him the EMCTAe and EMCIEe certifications on CLARiiON and EMCIE + EMCTA status on Celerra.
Currently Jon is contracted by a large multinational and part of a team that is responsible for running and maintaining several (EMC) storage and backup systems throughout Europe. Amongst his day-to-day activities are: performance troubleshooting, storage migrations and designing a new architecture for the Europe storage and backup environment.
This event ran from the 13th until the 31st of August .
Here is a summary document og the higlights of that discussion as set out by the experts. Ask The Expert: Performance Calculations on Clariion/VNX wrap up
The discussion itself follows below.
JonK1
247 Posts
0
July 23rd, 2013 02:00
If you run into performance problems on your front-end ports (e.g. high bandwidth, QFULL errors), you might want to rebalance your hosts over the existing or new FE ports. We've recently performed this kind of a change for a customer together with Rob. Our blogs are up here:
Rebalance VNX storage paths without downtime | FastStorage
Migrating hosts to new storage ports, LIVE | 50mu - about storage and how to access it
AneeshBhat
11 Posts
0
August 21st, 2013 02:00
Hi all, I Have a question regarding the throughput consideration,
Say there are 5 SSDs(3500 IOPS) with raid 5 , 5 SAS(180 IOPS) with raid 5 and 8 SATA(90 IOPS) with raid 6 configuration in FAST VP. Let there 50:50 read:write percentage.
Total front end IOPS for all three will be:
SSDs= 7000
SAS=360
SATA=205.7
[Formula used: frontend iops= (backend iops/(reads + {writes * write penalty})]
Total IOPS = 7565.7
Let the block size be 8k
Therefore the throughput= block size * IOPS = 59.1 MB/s
So even though front end port can support upto 1GB/s the maximum throughput this storage can support only 59.1 MB/s with all 8k blocks
similarly for 16k blocks throughput =118.2MB/s and for 64k = 472.8 MB/s.
My question is , Is this the right way to analyse storage throughput in terms of storage backend?
JonK1
247 Posts
0
August 21st, 2013 11:00
Hi Aneesh,
Your principe of calculating max bandwidth if you know the amount of IOps and the size of the IO is sound. It is indeed IOps * IO size = Bandwidth.
Also, you're right if you're talking about a sustained, random I/O, no-cache workload: that specific back-end will not be able to max out the front-end ports in terms of bandwidth.
As for the maximum throughput of the system: keep in mind that the CLARiiON and VNX systems have cache. Cache has a much higher burst rate than regular drives. Also, not all workloads are a worst case example: sequential workloads are more friendly on the back-end and thus can deliver more data which can fill up your ports. Backup workloads are pretty much almost 100% read I/O which also allows for a higher number of IOps. So you might just be able to saturate those front-end ports
Hope this helps!
AneeshBhat
11 Posts
0
August 21st, 2013 23:00
Hey Jon, thank you for the response. yes it helps ..
One more question i have is regarding the performance calculator that i have seen in few sites.
Say we take 5 SAS drives(180 IOPS) with raid 5.
100% read IOPS = 900
100% write IOPS = 225
50% read/write = 360
Formula used: frontend iops= (backend iops/(reads + {writes * write penalty})]
But when i did the same using performance calculator of a site my values matched with 100% read and 100% write but it didnt when it came to 50% read/write, it showed 562.5.
So after analyzing i came to a conclusion that they are coming to a linear approach i.e they are making 10 divisions of the difference of 100% read and 100% write and adding the value for for every difference in 10% read/ write..
ex: in this case
100% read IOPS = 900
100% write IOPS = 225
their difference would be 675 iops
dividing the value by 10 = 67.5
so when i take 50% read/write what they do is multiply 67.5 with 5 = 337.5 and then subtract this value 900
i.e 900-337.5 = 562.5 !
So instead of considering the formula for each read and write percentage they have considered a linear approach.
Is there any reason for calculating it that way?
Hope i have made myself clear with what i had to ask!
JonK1
247 Posts
0
September 19th, 2013 23:00
Hi Aneesh, sorry for the massive delay, I've been on holiday for the last couple of weeks.
I think you've made an error in your calculation. If you would take 562 front end IOps at a 50/50 R/W, you'd end up with roughly 280 read IOps and 280 write IOps. Write IOps times 4 for the WP will already exceed the total IOps capacity of the RG.
Circling back to the 360 FE IOps in 50/50 R/W, you'd have 180 reads and 180 writes. 180*4 = 720; add the 180 reads and you're back on the total of 900 IOps. So this is indeed the correct value.
AneeshBhat
11 Posts
0
September 21st, 2013 02:00
When I calculated I got 360. It is the calculators I found online that showed 562, which got me confusing!! Thanks a lot. It clears most my doubt. I even had discussion with one of the guys who had created the calculator, who said he was right. So came here to ask you guys , to make sure i wasn't wrong!!
Thanks a lot...
thereisnothinglikeabmw-gmail.com
10 Posts
0
June 4th, 2014 02:00
I was just stumped by this same question and I think you're right. Some sites with IOPS calculators use the formula below which doesn't seem right, and that's how they get the 562 in your example.
IOPS = (TOTAL_IOPS * %_Read) + ((TOTAL_IOPS * %_Write) / RAID_Penalty)
RRR
2 Intern
2 Intern
•
5.7K Posts
0
June 4th, 2014 04:00
You are right, they're deviding by the write penalty, which is clearly wrong. You must multiply!
IOPS = (TOTAL_IOPS * %_Read) + (((TOTAL_IOPS * %_Write) * RAID_Penalty))
vijayscsa1
26 Posts
0
June 30th, 2014 07:00
Hi...
I'm looking for a monitoring solution only for "VNX file OE performance" like data mover side , example: IOs, etc
I explored many tools in OpenSource like nagios etc, but didn't work as needed.
Please do suggest some options to have a performance monitoring for a group of 10 VNX File Arrays.
thanks,
Rainer_EMC
8.6K Posts
1
June 30th, 2014 08:00
UniSphere Central or VNX Monitoring and reporting
vijayscsa1
26 Posts
0
June 30th, 2014 23:00
Thank you, Rainer. Thank you so much.
Will Unisphere Central tool can be installed and used for a single point of managment console for around 40 VNX File Arrays?
Regarding the tool "VNX Monitoring and reporting" where can i find the information and installables.
Thanks for your inputs.
sagar666
1 Rookie
1 Rookie
•
6 Posts
0
September 11th, 2014 06:00
Hi,
We are using EMC clarion 240. I want to check throughput while my backups running and we don't have any analyzer installed in my box. Is is possible to achieve in command line?
Regards,
Vidya Sagar
Jim_Hegner
212 Posts
0
September 12th, 2014 00:00
You can set up VNX monitoring and reporting under a trial license,
This application works with CX4...
Very good tools and easier to use than Analýser.
RRR
2 Intern
2 Intern
•
5.7K Posts
0
September 12th, 2014 03:00
Another item you can check to get performance related data is the SAN ports! If you're using Brocade as your SAN, run the free tool "SAN Health" during the backup and make sure you have the tool gather performance data during the backup hours. For Cisco you might need Fabric Manager (or DCNM these days) to get performance data.
himanshi24
3 Posts
0
January 15th, 2015 13:00
Hello
In VNX what is maximum utilization of single SP like ( SP- A or SP - B) without any issue