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Kteixeira
Copper

MD3200 SAS Drive Performance

Hello Everyone,

Hoping I can acquire some tips from someone with prior experience in setting up the MD3200. I come from a FC IBM background so this is slightly different for me.. 

A little about my configuration

1 x MD3200 12 3TB 7200k drives (11 drives in a raid 5 with 1 global hot spare)

2 x Dell R620

2 x 6Gbps dual port HBA

Currently I have:

Port 0 of server 1 HBA connected to controller 1 port 0

Port 1 of server 1 HBA connected to controller 1 port 1

Port 0 of server 2 HBA connected to controller 2 port 0

Port 1 of server 2 HBA connected to controller 2 port 1

I have created 1 disk group raid 5 as stated above (27.236 TB) and 3 Luns,

1 GB

5TB

5TB

From this I have built a 2016 Hyper-V cluster. The issues I am facing is the write performance is extremely slow. I have deployed one virtual machine as a test. When copying files (5GB iso) from the local VM drive (Hosted on the SAN) speeds are fast 100+MB/s when transferring to the SAN the transfer starts out the same 100+ MB/s but then drastically drops averaging between 5-10 MB/s. I've been monitoring the current I/O latency and am seeing spikes from 0-200+ms. Everything on the SAN is claiming to be optimal. MPIO successfully installed, so I do not know what I am missing here. Hoping someone can give me a hand here.

 

Thanks in advance,

Kevin. 

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3 Replies
Moderator
Moderator

Re: MD3200 SAS Drive Performance

Hello Kevin,

Since you have a Dual controller MD3200, our best practice is to cable each host to both controllers.  Here is a link to our Deployment Guide & if you look on page 16 it shows you how you want your cable you MD3200. http://downloads.dell.com/manuals/common/powervault-md3200_deployment%20guide_en-us.pdf

Also, you will want to make sure that you are using the MPIO drives from the Resource DVD & not native MPIO.  Last thing is to make sure that your multipathing is set to Round Robin.

Please let us know if you have any other questions.

DELL-Sam L
Dell | Social Outreach Services - Enterprise
Download the Dell Quick Resource Locator app today to access PowerEdge support content on your mobile device! (iOS, Android, Windows)

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Kteixeira
Copper

Re: MD3200 SAS Drive Performance

Hello and thank you for your reply! 

My apologies I messed up my description regarding my connections. Each server has a dual port 6Gbps HBA with one connection to each controller. 

Port 0 of server 1 HBA connected to controller 1 port 0

Port 1 of server 1 HBA connected to controller 2 port 0

Port 0 of server 2 HBA connected to controller 1 port 1

Port 1 of server 2 HBA connected to controller 2 port 1

MPIO drivers were installed from the latest resource DVD.

I will change each of my multi path to Round Robin. This is the only change I will have to make. Will do some testing and get back to you. Thank you again for your response! 

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Kteixeira
Copper

Re: MD3200 SAS Drive Performance

Hey,

 

Just wanted to mention an oddity. On host one after changing MPIO policy to round robin with subset shows one path Active/Optimized and one Active/Unoptimized. On the second host one path is Active/Optimized and the other is in standby. I attempted to make it Active/Unoptimized however it keeps resetting back to standby. 

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