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NWT - Increase iSCSI Maximum Connections from 250

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Chilly_C
Occasional Advisor

NWT - Increase iSCSI Maximum Connections from 250

Is there a way with the Nimble Windows Toolkit to increase the maximum iSCSI connections from 250?  We have 5 Nimble arrays and I need more than 250 connections for the NWT software.

Thanks.

7 REPLIES
ndyer39
Honored Contributor
Solution

Re: NWT - Increase iSCSI Maximum Connections from 250

Hi Chris,

There are a few Windows Registry modifications that can be made to allow this to happen. If you open a case with Nimble Support they can guide you through this process.

Cheers

Nick

Chilly_C
Occasional Advisor

Re: NWT - Increase iSCSI Maximum Connections from 250

Thanks Nick.  I will contact Support.

Chilly_C
Occasional Advisor

Re: NWT - Increase iSCSI Maximum Connections from 250

Contacted Support but those Registry option don't work for this.  I have to be selective on my Veeam Proxy servers on which LUNs we use NWT with and don't.  The registry keys when changed do not take effect and when you restart the service it reverts them back to the original values.  So they are being read from another source I would think somehow.  If there are other suggestions feel free.

jbarnard71
Occasional Visitor

Re: NWT - Increase iSCSI Maximum Connections from 250

Microsoft supports only 256 iSCSI sessions per Windows OS.    One is reserved for Discovery, so you get  255.   NWT (NCM) reserves 5 for VSS Snapshots so you get 250.    If each target volume has 2 connections the number of volumes you could connect to would = 125.   The registry values are meant to change the number of connections per volume.   The default min.  is 2,  that will get you the 125.  If you increase it you decrease the number of volumes you can connect to.

Chilly_C
Occasional Advisor

Re: NWT - Increase iSCSI Maximum Connections from 250

I understand this but the min connections and max connections I want to set are 1.  Currently they are min 2 and max 8 right now but I cannot find a way to have them stay at 1 only. I don't need 2 connections and if I can get 1 per target volume then I can use 250 connections which is what I want.


When you change the registry settings like I said they don't take effect and if you restart the NWT (NCM) service it resets back to 2/8 respectively.  This is my dilemma.

ndyer39
Honored Contributor

Re: NWT - Increase iSCSI Maximum Connections from 250

If you only have 1 connection then that doesn't give you any resiliency on your network, this is why we do not allow setting 1 path only.


The only way I can think of resolving this is to remove NCM and use the Generic Windows iSCSI Initiator and mount the volume with 1 path only without any MPIO.

Chilly_C
Occasional Advisor

Re: NWT - Increase iSCSI Maximum Connections from 250

Yeah I may try this instead.  I don't need resiliency for pathing to the volumes as these are Veeam Proxy servers to allow SAN based backups and I only need the one path.  So seems like using the built in iSCSI is the way to go by the sounds of it.  I just like using the Nimble tools where possible.