Mellanox VLT-30111 4036 or VLT-30038 4036E??

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Nathan Ridge

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May 9, 2016
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Hi All,

I am wanting to buy two IB switches for vsan. I have been talking to supplier and can get the 4036 grid director VLT-30111 for $350 second hand or can also get the VLT-30038 4036E for $700 new. I am struggling to find too much online comparing the two and from a real world use what the differences would be??

Anyone that could shed some light on differences and if the VLT-30111 would be ample or go the 4036E?

cheers
 

T_Minus

Build. Break. Fix. Repeat
Feb 15, 2015
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E has 2x 10Gig Ethernet ports for briding IB network

Def. the way to go if you have a need to do that...
 

Nathan Ridge

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May 9, 2016
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i was just noticing the two ethernet ports on the side, other than that it looks the same? I was wondering about licensing, is there any gotchas or things i might not account for buying one of these switches? we will be using them in a pretty simple manner, two switches linked together into dual port qdr hcas on vmware
 

Nathan Ridge

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May 9, 2016
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I did see the Sun Oracle 602-4758-02 X2821A on ebay for $250, it looks the same as the 4036E with two net ports on the left side? anyone with experience with these? they are uber cheap for 36 port qdr
 

Nathan Ridge

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May 9, 2016
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so pretty much I would be paying double for 4036E over 4036 with only really the two Ethernet ports being the core differences? the straight 4036 do you know if it can be stacked simply by connecting the switch with a couple of short passive QRD QSF cables?
 

_alex

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Jan 28, 2016
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4036e is an IB <-> Ethernet Bridge/Gateway while 4036 is a managed IB Switch.
If you don't need to access Ethernet Networks from your IB 4036 would do.
Both have quite high power consumption, if you are fine with running a subnet-manager on your nodes you can also consider unmanaged IB-switches, what might work in your case. i have dual is-5022 in 1u and dual hba's in the nodes. power is about 50w each, in a compact 1u factor but fully redundant.
drawback is that opensm needs to run, only 8 Ports/Switch and breakout-cables are not supported.

(still looking for Information if qsfp to 4x sfp+ would work on 4036 .... )
 

EricP

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Jul 20, 2016
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4036e is an IB <-> Ethernet Bridge/Gateway while 4036 is a managed IB Switch.

(still looking for Information if qsfp to 4x sfp+ would work on 4036 .... )
No - not a gonna work. Why? sfp+ only works for ethernet. So in order for this to work you'll need an SX1012 (or similar ethernet/IB) switch. Think of it this way. The switch has to be new enough to recognize that the 4 wires inside the QSFP socket are going to 4 different end points. I was looking up these cables and their requirements on the Mellanox site and it also said that it's only for ethernet.

I was confused about "lossless" connections versus "unreliable datagram" and "reliable connected". "lossless" is for ethernet while datagram/connected is for IB (and IPoIB). Even datagram mode has CRCs so I shouldn't be seeing corruption but I'm at a loss to even find errors..

On a related note I've got silent data corruption (about 1 byte in every 1e6) using a VLT-30111 / Voltair 4036 & HP ConnectX-2 cards and it's driving me nuts trying to figure out why. I should not have flashed to the most recently HP firmware for the 4036. The corruption is much worse with RDMA and I'm not able to replicate it on a 2nd server - so it may be the ConnectX-2 card ?? or the switch?? but as it's a production server I can't touch it until things quiet down in a few weeks. This is for CentOS 6 on the NFS server and CentOS 6 or 7 on the NFS clients. The performance of even SDR IB was amazing compared to 10Gb ethernet.
 

EricP

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Jul 20, 2016
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so pretty much I would be paying double for 4036E over 4036 with only really the two Ethernet ports being the core differences? the straight 4036 do you know if it can be stacked simply by connecting the switch with a couple of short passive QRD QSF cables?
I'm quite sure that you can connect the two IB switches that way. It would not be a "stacked" connection the way it was with Nortel eth. switches I used - where they two switches are managed as a single one via a single IP. That was the era of 100Mb ports with a 2.5Gb interconnect card on the back and the interconnect card would let you "stack" them. Dirt cheap on EBay in the day - with 1Gb/s fiber modules. Mellanox equipment looks like it might do the same thing - a real price advantage over Cisco ethernet only switches. Right now I can get a SX1012 (12 ports at FDR and expands to 48 ports at 10Gb/s via the breakout cable) for the same price as a Cisco 36 port 1Gb/s switch.
 

Drewy

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Apr 23, 2016
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I think if you stacked them (I don't have experience of stacked 4036's) you would need to disable SM on one switch. Or somehow configure a SM master/slave relationship.
We have a number of stacked Oracle/Sun switches that are stacked (Exadata) and only one switch has SM running in master mode while all the others (per appliance) are slaves.