|
On Tue, 7 Mar 2006, Joseph L. Kaiser wrote:
Hi,
I have been tasked to mount a read-only NFS mounted
software area to 500+ nodes. I wanted to do this with NFS
and LVS, but after reading all the howtos with regard to
NFS and LVS and reading all the email with regard to this
in the archives (twice), it seems clear to me that this
doesn't work.
(I haven't done any of this, I've just talked to people - so
my knowledge is only theoretical).
(ro) is a different kettle of fish. If you use identical
disks (or identical geometry) and make the disks bitwise
identical (eg made with dd), then clients will always get
the same filehandle for the same file, no matter which
realserver they connect to. I assume you won't be able to
use RAID etc, just single disks.
For disk failure, make sure you have a few dd copies spare.
If you have to update files, then you'll have to do it
bitwise. I don't have any ideas on how to do this off the
top of my head. Even though you don't have the failover
problem anymore, you still can't do scheduled maintenance,
which is much the same thing.
However, I have a boss, and he wanted me to ask if turning
off no-attribute caching (noac) would help in the
reliability of this service.
If the disks are (ro) then the attributes on the server will
never change, in which case you want the client to cache the
attributes forever.
He has seen with another NFS mounted filesystem that using
the "noac" turns off caching and clients that sometimes
get "Stale NFS file handle" will reread the file and
succeed. So my question is:
Is "sometimes" an acceptable spec? Will it now pass the
tests in Sect 12.32.9. "stale file handles"
1. Has anyone seen this behavior with "noac"?
2. Does it make sense to try turning off "noac" and testing? Will the
filehandle problem still persist and make this just a dumb thing to do?
It will take you 10mins to do the tests in sect 12.32.9
(be sure to let us know the results)
Joe
--
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!
|
