There is a customer that has problems trying to boot devices from large ISO images using USB-R with Intel EMA
Is there any limitation in the size of ISO images when booting from USB-R?
After a while of trying to boot from USB-R image, the following message appears:
Regards and thanks in advance
Thank you for contacting Intel Customer Support.
I understand that your customer has problems trying to boot devices from large ISO images using USB-R with Intel EMA. I will be more than glad to help you today.
Can you please let us know what is the size of the ISO image that your customer is trying to load?
Is this error happens with different images?
Can you please confirm what EMA version is your customer running?
Intel® Endpoint Management Assistant (EMA) allows the option to mount the ISO file into the EMA storage section and send it to the endpoint machine.
Section 1.2.8 USB Redirection of the Intel® Endpoint Management Assistant (Intel® EMA) Administration and Usage Guide version: 1.5.1 (August 18, 2021) gives this option. (https://www.intel.com/content/dam/support/us/en/documents/software/manageability-products/intel-ema-...)
The USB Redirection (USBR) feature of Intel EMA allows you to mount a remote disk image (.iso or .img) to a managed endpoint via Intel AMT.
You can use this feature to mount a bootable image file and reboot a managed endpoint to a mounted image file or browse the mounted image content from the console of the managed endpoint via KVM (image must contain USB keyboard and mouse drivers for KVM interaction).
Once you have mounted an image file, you can reboot the endpoint to the mounted image.
See section 6.4.6 for details on how to mount an image to a managed endpoint.
See section 184.108.40.206 for details on rebooting to a mounted image.
Note: CIRA-based provisioning is highly recommended when using USBR. USBR is sensitive to latency, and Intel EMA has optimized USBR for CIRA provisioned endpoints.
If you are using TLS with relay, you will need to adjust the “USBR Redirection Throttling Rate” under the Manageability Server section in Server Settings as a Global Admin.
This setting is dependent upon your unique network environment. We recommend starting at a setting of 10 milliseconds and increasing it in increments of 10 until you find a rate that works well in your network environment. It is unlikely you would need to go above 50 milliseconds.
Note: Increasing this setting will decrease the USBR boot performance, especially for CIRA endpoints, and should only be used for TLS with relay-only instances. See section 1.2.6 for information about CIRA. See section 9.3 for information on setting Manageability Server settings.
The Storage page, accessible from the navigation pane at the left in the Intel EMA UI, lets you upload and store image files (.iso or .img) for later use in mounting to endpoints. See section 7 for details.
The following table lists the minimum Intel AMT versions required on endpoints to use USBR over CIRA:
Intel AMT Version Build Number
Intel AMT 11.8 all
Intel AMT 12 220.127.116.117 or later
Intel AMT 14 18.104.22.1681 or later
Intel AMT 15 all
We hope the information provided will be useful and we will be looking forward to your updates.
Intel Customer Support Technician
I answered several days ago, but I think I forgot to click on "reply" button
Customer is using EMA 1.5.1, and devices are provisioned using CIRA
Customer is testing with very large ISO files, 13 and 18GB. I have never tested so large images. This is the reason to ask if there is any limitation in the size (although there is nothing about it in the AMT/EMA documentation)
With smaller images (less than 1GB), customer says that some times fails, but most of the times works.
If using CIRA, could we also adjust the USBR Redirection Throttling Rate parameter?
Regards and thanks for your support
If the selected file's size exceeds the available disk space, an error message is displayed and the Upload button is disabled.
Review Section 9 "Appendix - Modifying Component Server Settings" for information on setting maximum storage capacity limits for each tenant as well as for the Intel EMA instance as a whole (under Manageability Server).
Intel® Endpoint Management Assistant (Intel® EMA) Administration and Usage Guide
You can find more details below:
UI: Maximum USBR Image Storage Capacity per Tenant
API: max Usbr Image Storag eCapacity Per Tenant In Gigabytes
Disk space in GB each tenant is allowed for USBR image storage.
- Default: 20 GB
- Maximum: 50 G
UI: Maximum USBR Image storage Capacity Per EMA Instance
API: maxUsbrImageStorageCapacityPer EmaInstance In Gigabytes
Total disk space in GB (for all tenants) allowed in this Intel EMA instance for USBR image storage.
- Default: 50 GB
- Maximum: 500 GB
Section 7.4 Image Recommendations
Use small images to the greatest extent possible, to prevent timeouts during endpoint reboot to a mounted image. Furthermore, if you plan to interact with the rebooted endpoint via KVM, the image you boot to must contain USB keyboard and mouse drivers.
One recommended method for endpoint reboot to a mounted image is to use a two-part image. First, boot the endpoint to a small image that allows you to bring up the endpoint on your network. Then use that image to access more content from the endpoint.
Note: There is a current known issue with Intel AMT booting some UDF formatted images via USBR. Sometimes UDF formatted images may not boot or may not boot fully. We recommend using CDFS formatted images until this issue is resolved.
In addition, to answer your question for USBR Redirection Throttling Rate, please find some details below:
UI: USBR Redirection Throttling Rate
API: usbrRedirectionThrottlingRateIn Milliseconds
The delay in sending USBR file data to the target endpoint's Intel AMT firmware. This is needed in order to throttle the data rate, as certain internal data flows within Intel EMA do not work properly if the data rate is too high.
Note: CIRA based provisioning is highly recommended when using USBR. USBR is sensitive to latency and Intel EMA has optimized USBR for CIRA provisioned endpoints.
If you are using TLS with relay, you will need to adjust the “USBR Redirection Throttling Rate” under the Manageability Server section in Server Settings as a Global Admin. This setting is dependent upon your unique network environment. We recommend starting at a setting of 10 milliseconds and increasing it in increments of 10 until you find a rate that works well in your network environment.
It is unlikely you would need to go above of 50 milliseconds. Note that increasing this setting will decrease the USBR boot performance, especially for CIRA endpoints, and should only be used for TLS with relay only instances.
Default value: 0, max value 1000, min value 0.
Suggested value = start at 10, increment by 10 to find appropriate rate for your network.
Additional details can be found in guide I shared before. Please let me know if you have any additional questions, and I will be glad to help you.
Intel Customer Support Technician
Thanks for your support
Customer is using UDF formatted images. The question from the customer is when is expected to have a fix forthe issue related to UDF formatted images
In the other hand, independtly of the UDF issue, and knowing that would be better using small images, is there any limit in the size o a image using to boot? I refer to AMT, I assume EMA (USBR storage capacity) is properly configured
Thank you for waiting for our updates.
The AMT interface that you are working with is 200 Kbs (bits), which isn't much at all. The intended usage was to bootstrap a small OS image to recover a larger general-purpose OS, to try to use this as a PXE server. There is some update coming to the documentation and a possible video tutorial to clarify and set expectations. Please keep check our support site for more information.
In case you need more assistance, please contact us back.
Thanks for your answer.
Just one question: if booting from a ISO using AMT fails, is there any log at EMA server to know if the failure is related to a timeout, using a UDF formatted image or any other reason?
You can try to find this information by running the EMA logs:
The Intel EMA Agent generates the following logs:
- a general log for errors encountered when the Agent is running
- a debugging log for debug information
- an installation log if any errors are detected during the
General Intel® EMA Agent error log
The general log is enabled by default, and it reports Intel® EMA
Agent service errors. The file name is EmaAgent.log.
The EmaAgent.log file is located in the Intel® EMA Agent installation directory in the Program Files x86 folder for win32 or
the Program Files folder for win64.
Logs include the date and time of the error, the path and file name of the error, line numbers, parameters, and a brief description of the error.
Log file syntax:
[Date & Time] FilePath: LineNumber (Parameter1, Parameter2) Message.
Intel® EMA Agent installation log
This log is generated when an error is detected during the install/uninstall process. The log file is named after the installer
used, and is located in the same folder where the installer is located. If no errors are detected during the install/uninstall
process, the log is not created.
Note: To address the specific error message “Error removing the installation directory file,” ensure there are no open or protected files in the installation directory when uninstalling. Be sure to close all files before starting the uninstall.
You can find more additional information here:
Intel Customer Support Technician
For firmware updates and troubleshooting tips, visit :https://intel.com/support/serverbios
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Intel Technical Support Technician