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Altecice

Low I/O performance with ESXi 6.0

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Altecice

Hey guys I wonder if anybody can help me with an issue I am having. 

 

 

Some background of my setup:

  • I am using the inbuilt B120i RAID controller and have all 3 drives set up in there own Array as logical drives (everything else is defaults).
  • HP ESXi 6.0 installed a class 10 32gb Micro-SDcard.
  • W2012 R2 installed on the SSD.
  •  I have added both of the 500GB HDDs to the VM via SCSI virtual disks (the ESXi default)
  • Everything is Thin Provisioned.
  • Full 1Gbit wired connection
  • Using the first NIC port as a shared ILO.

 

The issue I am having is when I create a simple shared folder on my W2012 R2 server (SMB share) I try to write a large single 20GB ISO to one of the 500gb drives it sits at around 112MB/s for about 30% of the file but will then quickly drop down to <10MB/s. I have tried creating network shares on all 3 drives and all 3 do the exact same thing. Copying a file from a share to my desktop on my network is nothing to shout about (25-35MB/s). 

 

Small files are 1-3MB/s

 

Has anyone encounted this before? Im not really sure where to start pointing the finger, I know the drives are much quicker than 10MB/s, Could it be somthing to do with ESXi or the B120i controller even though I have nothing in RAID only single arrays? 

 

Thanks.

Edited by Altecice

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schoondoggy

Did you have an older version of ESXi running before 6.0?

Where are you copying the 20GB ISO from?

What does your network look like? What is the switch?

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Altecice

Did you have an older version of ESXi running before 6.0?

Where are you copying the 20GB ISO from?

What does your network look like? What is the switch?

 

Nope its a brand new server with 6.0 stright onto it.

the 20GB ISO is being moved from a 2TB HDD from my personal desktop over the network to the server (to the shared folder on the server)

My network is a very simple SOHO, I have a Virgin Media SuperHub 2 with four 1gbit ports on the back and my desktop is in one and the server in the other. 

 

Im wondering if its worth testing without using the Inbuilt raid controller and placing the system in AHCI mode.

Edited by Altecice

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schoondoggy

I would try a direct cable connection from your PC to the server to rule out your router. A standalone Ethernet switch is preferred to the switched ports in a router.

When the connection slows to 10MB, check the network properties on both the PC and server to confirm they are both still running at 1Gb. 10MB is about the max you get from 100Mb Ethernet.

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Altecice

I would try a direct cable connection from your PC to the server to rule out your router. A standalone Ethernet switch is preferred to the switched ports in a router.

When the connection slows to 10MB, check the network properties on both the PC and server to confirm they are both still running at 1Gb. 10MB is about the max you get from 100Mb Ethernet.

 

Ahh yes, that would be a great idea to take away the router variable. I will report back soon.

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Altecice

I would try a direct cable connection from your PC to the server to rule out your router. A standalone Ethernet switch is preferred to the switched ports in a router.

When the connection slows to 10MB, check the network properties on both the PC and server to confirm they are both still running at 1Gb. 10MB is about the max you get from 100Mb Ethernet.

 

Ok I have tried it directly connected and the same thing happens. On my VM I have tried using the E1000E and the 10Gbit version. I have them both my computer and the server set to force 1Gbit connection speed and its still the same.

 

Other things I have just tried is not using the inbuilt RAID and AHCI + downgrading from ESXi v 6.0 to 5.5. Still nothing :(.

 

I also tried another .ISO file and it will pin at 112MB/s for about 2.5-3GB and then plummet.

Edited by Altecice

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schoondoggy
Altecice
Altecice

 

I have just noticed a strange thing happening on my 2012 VM. I have assigned it 4Gb of RAM. it sits around 512mb usage on desktop but increases as I transfer something to it (as if its RAM caching it) the 'modified' ram usage in Resource Monitor increases to 1.5GB and once it does that my speed dip always happens 

Meanwhile while my speed takes a hit the 'modified' section of the RAM is shrinking back down so my total RAM usage is once again 512.

 

Reading from the server disk to my desktop on the other hand is perfect 100MB/s for the full .ISO.  So it seems to be somthing to do with RAM cache when writing to my disks ? 

Edited by Altecice

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GotNoTime

I have just noticed a strange thing happening on my 2012 VM. I have assigned it 4Gb of RAM. it sits around 512mb usage on desktop but increases as I transfer something to it (as if its RAM caching it) the 'modified' ram usage in Resource Monitor increases to 1.5GB and once it does that my speed dip always happens 

Meanwhile while my speed takes a hit the 'modified' section of the RAM is shrinking back down so my total RAM usage is once again 512.

 

Reading from the server disk to my desktop on the other hand is perfect 100MB/s for the full .ISO.  So it seems to be somthing to do with RAM cache ?

The b120i driver uses system RAM for caching. Somebody mentioned that the b120i ESXi driver doesn't allocate much cache. I've not tested it myself.

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