CIFS? Really?

Posted Feb 9, 2007 23:14 UTC (Fri) by drag (subscriber, #31333) [Link]

OpenAFS I've used before. It's very nice for networks were you have large amounts of distributed users over insecure and unreliable networks.

Say if I wanted to do file sharing over a widespread campus with heavy use of wireless then OpenAFS would entirely kick-rear. It has heavy local cache and has acceptable levels of authentication (kerberos 4) and crypto (not aas strong as ssh, but better then CIFS).

A person can be using OpenAFS, editing files on it and such, loose the connection to the server (temporarially) and still be able to work with their files. Also you can move and mirror volumes from server to server and it is completely transparent to the end users becuase it uses a world-wide directory system were you have mount points and such, similar to Unix directory system.. rather then "server:/share" model for NFS or other common network fs's.

However it has severe limitations. It won't handle large files well at all. Completely unsuitable. It's for small text files. Volumes are non-native to Linux.. you need to have OpenAFS running to access the files on the server which can complicate recovery. File permissions are not POSIX. Volume sizes are severly limited.

User training is hard. Since it's not posix file permissions are very confusing and overall it's confusing to people used to using computers.

The upshot is that since it's been open source'd it's stability and usefullness has increased dramaticly and it has a healthy development community.

Lustre is very very interesting. Lustre folks have contributed a lot of improvements to Ext3 and will have a lot of involvement in Ext4, I beleive. Its a POSIX fs, it supports Linux-style ACLs, and most of the important bits that it uses are already in the kernel and being used in other FS's.

Performance is very very high. It's been used to break speed records.

It's very distributed and has lots of failover features. Seperate Metadata servers, volume servers, distributed lock server, etc. Performance and scalability can be very good as your files aand volumes will be distributed across many machines. You can agregate bandwidth and other stuff.

It can tie into SANs, or be used off of PC hardware. Supports all the hip stuff like remote DMA, exploit gigabit ethernet/fiberchannel/infinaband fully.

It's efficient, claiming in benchmarks to get 944Mb/s file transfer performance on a gigabit network.

blah blah blah.

Pretty much any sort of file system feature you could ever want in a distributed clustering file system in the enterprise is aviable in Lustre.

Then you have the ability to export volumes so that they can be accessed via NFS or CIFS.

The major downside right now is that it's going to be hugely complicated to deploy. Also there is no strong security for it right now, due it being targetted for high performance computing applications before being general-use (which it's aiming for). Hopefully by the end of this year they will get initial support for Kerberos and other strong security models.