RB450G 100% CPU usage when copying files to micro SD card

RouterOS General
1

I can’t get reliable micro sd card file transfer on RB450G.

Each time i try to copy a file, CPU goes to 100%, Winbox loose communication with Routerboard, and FTP file transfer abort after 10 or 20 seconds.

I’m using a Transcend 2 GB sd Card. The same card is working nicely on a USB to micro SD adaptor on a PC. This card works correctly as well on others hardware.

When formatting the card, winbox loose communication after a few seconds. I Need to reconnect Winbox when formatting is ended.

Last, when copying files to the NAND memory, transfers are reliable, but CPU goes to 100% as well.

Seems like there is a firmware or hardware problem here, it is not normal that CPU goes to 100 % for such slow files transfers. We should have only a couple % load on a 680 MHz CPU. Pooling seems to be used instead of interupt, or there is a problem in the interupt routine.

Main use of the sd card would have been to store PXE boot images.

2

Hello,

It’s a problem with the routerboards.

To read/write compact flash or SD cards the board uses the CPU, because don’t have read/write chip. All is done by CPU. For this reason you can’t use a compact flash to make populated cache with ip/proxy option neither.

I hope this helps understanding the problem : /

3

Even if hardware has no DMA controller, i think that it should be possible to modify, rewrite or use another read/write driver to get a lower CPU charge.