[OmniOS-discuss] Testing RSF-1 with zpool/nfs HA

[Schweiss, Chip]

On Thu, Feb 18, 2016 at 5:14 AM, Michael Rasmussen <mir at miras.org> wrote:

> On Thu, 18 Feb 2016 07:13:36 +0100
> Stephan Budach <stephan.budach at JVM.DE> wrote:
>
> >
> > So, when I issue a simple ls -l on the folder of the vdisks, while the
> switchover is happening, the command somtimes comcludes in 18 to 20
> seconds, but sometime ls will just sit there for minutes.
> >
> This is a known limitation in NFS. NFS was never intended to be
> clustered so what you experience is the NFS process on the client side
> keeps kernel locks for the now unavailable NFS server and any request
> to the process hangs waiting for these locks to be resolved. This can
> be compared to a situation where you hot-swap a drive in the pool
> without notifying the pool.
>
> Only way to resolve this is to forcefully kill all NFS client processes
> and the restart the NFS client.
>
>
I've been running RSF-1 on OmniOS since about r151008.  All my clients have
always been NFSv3 and NFSv4.

My memory is a bit fuzzy, but when I first started testing RSF-1, OmniOS
still had the Sun lock manager which was later replaced with the BSD lock
manager.   This has had many difficulties.

I do remember that fail overs when I first started with RSF-1 never had
these stalls, I believe this was because the lock state was stored in the
pool and the server taking over the pool would inherit that state too.
That state is now lost when a pool is imported with the BSD lock manager.

When I did testing I would do both full speed reading and writing to the
pool and force fail overs, both by command line and by killing power on the
active server.    Never did I have a fail over take more than about 30
seconds for NFS to fully resume data flow.

Others who know more about the BSD lock manager vs the old Sun lock manager
may be able to tell us more.  I'd also be curious if Nexenta has addressed
this.

-Chip


> --
> Hilsen/Regards
> Michael Rasmussen
>
> Get my public GnuPG keys:
> michael <at> rasmussen <dot> cc
> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xD3C9A00E
> mir <at> datanom <dot> net
> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xE501F51C
> mir <at> miras <dot> org
> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xE3E80917
> --------------------------------------------------------------
> /usr/games/fortune -es says:
> The founding fathers tried to set up a judicial system where the accused
> received a fair trial, not a system to insure an acquittal on
> technicalities.
>
> _______________________________________________
> OmniOS-discuss mailing list
> OmniOS-discuss at lists.omniti.com
> http://lists.omniti.com/mailman/listinfo/omnios-discuss
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://omniosce.org/ml-archive/attachments/20160218/c506318e/attachment-0001.html>