Linux CIFS Client

This article was first written in February 2006 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/328).

Extract from the Linux CIFS Client homepage:

The CIFS VFS is a virtual file system for Linux to allow access to servers and storage appliances compliant with the SNIA CIFS Specification version 1.0 or later. Popular servers such as Samba, Windows 2000, Windows XP and many others support CIFS by default. The CIFS VFS does not provide support for older servers based on the more primitive SMB (Server Message Block) protocol (you can use the Linux filesystem smbfs for these).

CIFS VFS is designed to take advantage of advanced network filesystem features such as locking, Unicode (advanced internationalization), hardlinks, dfs (hierarchical, replicated name space), distributed caching and uses native TCP names (rather than RFC1001, Netbios names). Unlike some other network filesystems all key network function including authentication is provided in kernel (and changes to mount and/or a mount helper file are not required in order to enable the CIFS VFS).

[…]

The CIFS VFS has been tested with Linux 2.4.14 and later as well as regular testing on Linux 2.6 (and has been in the kernel source starting with Linux kernel 2.5.42. The CIFS client is no longer considered “expiremental” in Linux versions after 2.6.7 (cifs version 1.19) or later. Testing has been done on various hardware architectures including x86 and even big endian zSeries hardware. The cifs and smbfs filesystems can coexist on the same system and do not conflict.

So, it is usually safer nowadays to use the cifs filesystem type instead of the smbfs for reasonably recent SMB/CIFS server implementations. The options available are almost identical between both, and you will probably avoid errors like this one: smb_proc_readX_data: offset is larger than SMB_READX_MAX_PAD or negative!

HOWTO Activate kernel oplocks in Samba on Debian GNU/Linux (up to Sarge)

This article was first written in February 2006 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/327).

Starting from kernel 2.4, Linux has got the kernel oplocks feature. Kernel oplocks would permit Samba to share locks with the UNIX filesystem, to allow local Linux applications or applications accessing the files through NFS for example to be notified of files already opened for writing by a client using SMB.

Sadly, the Samba package in Debian GNU/Linux up to Sarge disable this feature to keep compatibility with kernels strictly inferior to 2.4.

To activate it, you then have to rebuild the package, after commenting the lines disabling this feature in the file debian/config.cache of the package sources. Those following lines are the ones to comment:

samba_cv_HAVE_KERNEL_OPLOCKS_LINUX=${samba_cv_HAVE_KERNEL_OPLOCKS_LINUX=no}
samba_cv_HAVE_KERNEL_CHANGE_NOTIFY=${samba_cv_HAVE_KERNEL_CHANGE_NOTIFY=no}
samba_cv_HAVE_KERNEL_SHARE_MODES=${samba_cv_HAVE_KERNEL_SHARE_MODES=no}

Commenting the next lines would probably allow you to enable even more features.

Sun Solaris

This article was first written in February 2006 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/326).

Sun Solaris is probably today’s most-used UNIX OS around, probably due to its security and high-performance approach. It has been traditionally running mostly on SPARC, a little on Intel platforms, but is now happily running on AMD64 also.

Lately, Sun decided to opensource it, and everybody should probably be happy of this move. The Open Source version’s name is OpenSolaris, and various distributions [1] (or variants) already exist.

[1] like Nexenta, Schilix or Belenix

HOWTO Setup Bonding Ethernet on Debian

This article was first written in February 2006 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/325).

This technology is meant to merge several network links into one logical, providing with higher availability and higher throughput (while it is not absolutely necessary to use both aspects at the same time).

Some vendors call it Trunking (ex.: Sun) or Link Aggregation. It’s all the same technology, and they communicate together rather well.