I see another article asking this simple question and never answered. Applications such as BackUp Exec as well as random disconnects to iSCSI drives during our testing in 2012 R2 all suggest the ol' IRPStackSize value needs to get set (Symantec suggests 30 decimal). Why are we having this basic networking problem in 2012R2 64bit OS & 10GB Nic's? Is this value still valid to use in newer OS's?

 

Hi,

There are many factors that could cause random disconnects to iSCSI drives. You could increase the IRPStackSize value to check if it can resolve.

If the issue still exists, please provide error message in the event log for our further research. 

Best Regards,

Mandy 

 So you are suggesting that although I cannot find any documentation to confirm, the value still is valid and can be used to troubleshoot network performance issues? So here is the next part of the question, it is on a VM so does the value require to be changed both on the VM + the actual HOST ? Currently for performance reason we only assign 1 VM per NIC so the HOST has a total of 10 NICs (2x4 ports x1GB & 2 ports x 10GB).

Hi,

Do you connect iSCSI drives to a VM or the actual HOST? If connect to a VM, the value require to be changed on the VM. It might be necessary to increase the IRPStackSize value for certain transports or if you have many file system drivers installed on the system.

Description of the IRPStackSize parameter in Windows 2000, in Windows XP, and in Windows Server 2003
http://support.microsoft.com/kb/285089/en-us

Best Regards,

Mandy 

 Yes, iSCSI NIC's are attached to the VM's & yes I did change the setting on the VM but one would think it would also need to be changed on the host as well (same that you enable jumbo frames on the VM and must enable them on the physical NIC on the host). But again, as per your URL reference & the point of this thread, is why is everyone pointing me to the article I am fully aware of that only speaks of 2000/2003/XP/NT4. It seems this value is still valid yet no documentation exists for it. My question revolves around any new limitations or features  (like known settings of 30-38 cause system instability, max setting is 50), perhaps I can exceed 50 now, or anything else but no documentation exists for this setting on a 2012/2012 R2 environment.

Hi,

I think we only need to increase the IRPStackSize value on the VM. iSCSI allows two hosts to negotiate and then exchange SCSI commands using Internet Protocol (IP) networks. We dont need to increase the IRPStackSize value on the host.

Since the article that I mentioned is applied to 2000/2003/XP/NT4, you could try the setting on a 2012/2012 R2 environment.

Server Service: IRP Stack Size Monitor
http://mpwiki.viacode.com/default.aspx?g=posts&t=166111

Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

Best Regards,

Mandy 

Hi,

I would like to confirm what is the current situation? Have you resolved the problem?

If there is anything that we can do for you, please do not hesitate to let us know, and we will be happy to help.

Best Regards,

Mandy

Well some of it has been resolved with changes in setup across the board (iSCSI issues we did firmware updates on device & NIC driver updates). However, the root of this questions still remains, where is the documentation for this value in newer Server OS's? That has still not been addressed nor when making changes if both the host and VM must make the required registry changes. I know you said you 'think' the VM but where is the documentation?

Hi Partner,

Sorry for the delayed response.

Based on my research, I'm sorry that currently it appears that there is not an official documentation which describes the IRPStackSize in newer Server OS, like Windows Server 2012/2012 R2. However, I find a related article which suggests the recommended value of IRPStackSize on Windows Server 2012 systems. You can use it for a reference, especially the "[Windows]: IrpStackSize should have the recommended value" section.

Best-Practices Remediation Tips for Server 2012 Pt I

https://www.myotherpcisacloud.com/post/2012/11/11/Best-Practices-Remediation-Tips-for-Server-2012-Pt-I.aspx

[Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.]

At the meantime, we can follow the steps below to determining an appropriate size of IRPStackSize:

1. Set the value from 20, increase the value even more

-- Generally, the IRPStackSize value range is from 11 (0xb hexadecimal) to 50 (0x32 hexadecimal).

2. IRPStackSize registry key name is case sensitive

3. When you set the value, restart the Server service instead of rebooting system

Hopefully this can help.

Feel free to let me know if you have any questions. Thanks for your time.

Best Regards,

Soph

 I'll set it and range it through, given I have 3 NIC's (1xLAN, 2x iSCSI), I will probably go 3x15 = 45 decimal as the basic setting.

Hi Partner,

Thank you for your reply.

Currently, let's monitor the changes for a while. Please let me know if there is any update after that. Thank you for your time.

Best Regards,

Sophia Sun

Hi Partner,

Hope you are doing well.

Do you have any update about this issue? If there are anything I can help, please feel free to let me know.

Best regards,

Sophia SUn

 Seems stable with a setting of 45 (decimal) and performance is as expected for the iSCSI connections.