IOx Access to USB Storage

Improvements

IOx Access to USB Storage

Customers have requested the ability to mount the host a USB thumb drive within the Docker container running on IOx. The bootflash has a limited number of read/write cycles, and a container continuously writing on the eMMC would prematurely wear out the unit. Using the USB thumb drive will allow Docker containers to write in a continuous manner without compromising the integrity of the bootflash.

Feature Requirements and Limitations

The following apply to this feature:

1. The filesystem types supported for USB thumb drives on the IR1101 are: VFAT, EXT2 and EXT3. However, IOx only supports mounting of USB thumb drives with EXT2 and EXT3 filesystem. Cisco recommends EXT3 for the following reasons:

• EXT3 is a journaling filesystem, which means there are not fragmentation issues.
• Read/Writes are significantly faster with EXT3 filesystems
• VFAT has a 4 GB maximum file-size limitation, which is a problem with container continuously writing large files.

1. If the USB thumb drive is removed while a write operation by IOx apps is in progress, all the files included in the copy operation will be lost.
2. If the USB thumb drive is removed while IOX and the app are using it, IOX will still be in running state. The functionality of the app using USB thumb drive as storage will be severely impacted, since it will not be able to read and/or write on the USB thumb drive.

Making the USB Thumb Drive Available to the IOx App

In order to make the USB thumb drive available to the IOx app, you need to issue a run option. See the following example:Router(config-app-hosting-docker)#run-opts 1 "-v /mnt/usb0:/usbflash0"