2.4 gets symlink cache!

2.4 gets symlink cache!

Post by Ian G Batt » Sat, 18 Feb 1995 00:37:54



Why did no-one tell me?  Why wasn't it mentioned?  
nfs_do_symlink_cache is set to 1 by default, and boot-and-login yields
about 3 readlink operations as reported by nfsstat -c.  Set it to 0 (or
use 2.3) and it takes about 70 here (we use amd, which means that a lot
of readlinks are local to the machine, but are readlinks none the less).
Symlinks have gone back to the server since NFS has been around, and at
last it's been fixed!

ian

 
 
 

2.4 gets symlink cache!

Post by Jim Dav » Sat, 18 Feb 1995 04:03:27



:Why did no-one tell me?  Why wasn't it mentioned?  
:nfs_do_symlink_cache is set to 1 by default, and boot-and-login yields
:about 3 readlink operations as reported by nfsstat -c.  Set it to 0 (or
:use 2.3) and it takes about 70 here (we use amd, which means that a lot
:of readlinks are local to the machine, but are readlinks none the less).
:Symlinks have gone back to the server since NFS has been around, and at
:last it's been fixed!

I don't use amd, but according to traffic on the amd-workers mailing
list, that symlink caching will cause trouble unless you have the
current, upl90, release (ftp://ftp.cs.columbia.edu/pub/amd).
Otherwise, you can disable caching with 'set nfs:nfs_do_symlink_cache= 0'
in /etc/system, but it does seem a shame to have to disable such
a nice feature...

 
 
 

1. symlink values cache in Solaris 2.4 (hlfsd was broken)

Erez> James and I finally managed to find out why hlfsd was so broken
Erez> on Solaris 2.4 (sparc, didn't test x86 yet).  It was broken b/c
Erez> Solaris 2.4 has another optimizing hack --- a special cache
Erez> which probably maps symlink names+mtimes to their values... or
Erez> so we think.  This is to optimize performance, but of course it
Erez> severely affected hlfsd; users were getting the /mail/home
Erez> symlink pointing to other pervious person's links b/c of the
Erez> cache.

If my memory serves me well, we (Dave Rich and I) discovered a similar
"feature" in unicos 8.X.  Took a similar amount of sleuthing to find
it.  We ended up having to turn off the symlink cache for the whole
OS, whch was not to difficult to do through normal system
configuration under unicos.

stephen.

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5. scheduler cache affinity improvement for 2.4 kernels

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7. How can I disable disk caching altogether on kernel 2.4?

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