Hi,

I've just got through the forum in search of performance-related topics. Unfortunately I didn't manage to find an answer I was looking for. Namely, how many MB/s one can get on CBFS for both read and write operations. I mean normal use case for example windows embedded drag and drop copy mechanism.

We want to implement something like SFTP Net Drive but faster. On my computer SFTP Net Drive was able to achieve less than 5MB/s and we need to know whether the bottleneck is CBFS or the SSH part of this software.

Bandwidth of around 100Mbps is critical for us, 1Gbps is most welcome.

Cheers,
Wojtek

You've made my day with your requirements :).

Yet CBFS also adds to slowdown due to necessity to call the user-mode code, so your question is partially applicable. But unfortunately no satisfactory (for you) answer can be given, and here's why. SFTP is a complicated protocol where data is wrapped into several packages one in another. All of this takes time. Encryption is also quite slow process. 10 MBps is probably a limit for SFTP even in properly setup and capable environments.

Hi,

thank you for a really quick answer.

I'm fully aware of the context switches and their influence on performance (especially IO performance).

As far as I know both sshfs and scp are capable of transferring up to 40MB/s. We are just wondering about whether it is possible to get this much from CBFS or it is going to be the factor limiting our performance and we need to fall-back to kernel programming anyway.

Cheers,
Wojtek

I don't know what sshfs is, and SCP is not SFTP. SCP is run over SSH1 and there's a different procedure of packet handling there. To answer your question - build a test and measure.

Also I made a typo when writing - 10 MBytes per second is near the upper limit, not 10 mbit/s. What you are referring to is about 4.5 MBytes per second.

In my project files are copied through network with my own file transfer protocol and i can easily achive speeds up to 50/60 megabytes per second. So that would conclude that it is possible to have a high performance with CBFS. The only case where the performance lets down is when you have to much random access,small data block read writes and attributes beign set on files. But even so the performance was greatly imporved by CBFS Development team when they implemented kernel caching in latest build.

You should definitely give it a try , the programming api is ridiculosly easy ;)

Thanks for the answers.

It looks like it's worth giving a try. I will let you know if we manage to outperform SFTP NEt Drive.

Best,
Wojtek