Re: Samba or NFS
On Sat, 2011-06-04 at 15:27 -0400, Nico Kadel-Garcia wrote:
> On Sat, Jun 4, 2011 at 1:33 PM, John A. Sullivan III
<snip>
> File ownership is a constant confusion between the two basic systems.
> *DO NOT* try to manage the same file server and accessing its material
> with the two different protocols. I've been this route, the claims of
> "just set this" are generally complete handwaving, and cleaning up
> when they break down can be a nightmare. I've been down this route
> with Linux and UNIX and Windows file servers and NetApps, and I don't
> recommend doing multiple access for *any* of them.
>
> And don't get me *started* on the iSCSI pain, sorrow, and blood in the streets..
>
>
Boy have we really digressed on this thread! If anyone objects, please
say so and I'll spawn another one.
I'm glad you mentioned trying to run both protocols against the same
file system. IF we go the NAS (presenting a remote file system as a
remote file system - to define terms) rather than the SAN (presenting a
remote file system as a block device) route, being able to access the
same data on the NAS via both protocols would solve a big headache for
us (Windows and Linux users both needing read/write access to the same
data). Has anyone been able to successfully do this?
Otherwise, we will probably use SAMBA rather than have to license NFS
services on Windows (not sure if that's still a separate license).
I'm also curious to see how others have dealt with iSCSI. That set back
our entire company launch by five months as we fought ISCSI / Linux file
system issues until we realized the problem was the 4KB block size
limitation in Linux. Because each iSCSI block needs to be acknowledged,
with only 4KB blocks, latency becomes the bottleneck rather than
bandwidth, i.e., 4KB of data comes nowhere close to saturating the
network. Thus, the maximum iSCSI throughput becomes 4KB/(round trip
latency), e.g., 100 microsecond round trip latency limits throughput to
4KB/.0001 = 40MBps.
To make matters worse for us, we are using Nexenta as a SAN. It's a
brilliant idea of using ZFS for a back end but it runs on OpenSolaris
and the network stack is much slower than Linux. We are eagerly waiting
for BTRFS to mature as we suspect we will see a 30% to 80% increase in
throughput by moving to Linux based SANs.
In any event, has anyone found a way around this iSCSI 4KB problem for
Linux file I/O?
And to restate the earlier question, has anyone truly resolved the
issues of running SAMBA and NFS against the same back end Linux file
system?
Thanks. Very helpful thread - John
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