SUMMARY: EMC dual-attached, no metadata updates visible

From: Philipp Buehler <pb-sunmanagers_at_mlsub.buehler.net>
Date: Tue Dec 14 2004 - 02:05:12 EST
Hi,

long story short: it cant work with UFS

Thanks to Darren Dunham and DJ Gregor

> > Hello,
> > 
> > 2 Solaris 8 02/04 machines connect to the same 35GB slice on
> > an EMC symmetrix.
> > Box1 mounts this slice RW, the other Box2 (of course) RO.
> 
> You say "mount".  Is this a filesystem?  If so which one?
> 
> Neither UFS nor the normal version of VxFS will support this.  It can
> cause simple problems all the way to panics on the RO machine.
> 
> > This works so far, and I am seeing testfiles on both machines,
> > so I really connect to the same slice (cannot control the EMC, btw).
> > 
> > Yet, box1 writes a new file to the slice and this new file cannot
> > be seen on box2 until I umount/mount the slice again. Same for any
> > other metadata update.
> 
> Correct.  UFS/VxFS assumes one mounter only.  So it never expects the
> disk to be updated and that anything cached is always valid.  
> 
> > First I thought the kernel-cache on box2 is tricking me, so I mounted
> > on box2 w/ ro,forcedirectio -> same effect.
> 
> Can't do it.  You'd need another filesystem to do this....
> 
> Veritas Cluster Filesystem
> Sun's SAMFS
> Sun's gfs (part of SunCluster I think?)
> ADIC has a product.  There's probably one or two others out there.
> 
> > I am stuck here.. I was googling quite a while, but only found problems
> > where the slice couldnt be seen on box2 at all - usually EMC-side config
> > problems, so that didnt help me further.
> > Also in Sun Cluster setups there would be a different kernel/drv/sd to 
> > be loaded. I didnt try that so far, since I do not know what the
> > difference is and where to get this "other" sd kernel-module.
> > 
> > From my understanding there's either callback hook missing by means that
> > a write to the emc-slice will tell box2's sd to refresh metadata or
> > it cannot work at all?
> 
> Has nothing to do with EMC or anything.  This is simply not supported
> with UFS.
> 
> http://www.sunmanagers.org/pipermail/summaries/2003-April/003605.html
> http://www.sunmanagers.org/pipermail/summaries/2003-March/003330.html
> 
-- 
Philipp Buehler, aka fips | <double-p>

cvs -d /dev/myself commit -m "it's my life" dont/you/forget
_______________________________________________
sunmanagers mailing list
sunmanagers@sunmanagers.org
http://www.sunmanagers.org/mailman/listinfo/sunmanagers
Received on Tue Dec 14 02:05:17 2004

This archive was generated by hypermail 2.1.8 : Thu Mar 03 2016 - 06:43:40 EST