[pve-devel] ZFS Storage Patches

[Chris Allen]

> It was also part of latest 3.1. Double-click the mouse over your
> storage specification in Datacenter->storage and the panel pops up.
> Patched panel attached.

Thank you, I was unaware of this.


> BTW. Have you made any performance measures sparse vs non-sparse and
> write cache vs no write cache?

No I haven't.  As far as I understand it sparse should not affect
performance whatsoever, it only changes whether or not a reservation is
created on the ZVOL.  Turning of write caching on the LU should decrease
performance, dramatically so, if you do not have a separate and very fast
ZIL device (eg. ZeusRAM).  Every block write to the ZVOL will be done
synchronously when write caching is turned off.

I've done some testing with regards to block size, compression, and dedup.
 I wanted sparse support for myself and I figured while I was there I might
as well add a flag for turning off write caching.  For people with the
right (and expensive!) hardware the added safety of no write caching might
be worth it.

Have you tested the ZFS storage plugin on Solaris 11.1?  I first tried
using it with 11.1, but they changed how the LUN assignment for the views
works.  In 11.0 and OmniOS the first available LUN will get used when a new
view is created if no LUN is given.  But in 11.1 it gets populated with a
string that says "AUTO".  This of course means PVE can't connect to the
volume because it can't resolve the LUN.  Unfortunately I couldn't find
anything in the 11.1 documentation that described how to get the LUN.  I'm
assuming there's some kind of mechanism in 11.1 where you can get the
number on the fly, as it must handle them dynamically now.  But after a lot
of Googling and fiddling around I gave up and switched to OmniOS.  I don't
have a support contract with Oracle so that was a no go.  Anyway, just
thought I'd mention that in case you knew about it.

In addition to that problem 11.1 also has a bug in the handling of the
iSCSI feature Immediate Data.  It doesn't implement it properly according
to the iSCSI RFC, and so you need to turn of Immediate Data on the client
in order to connect.  The patch is available to Oracle paying support
customers only.


On Thu, Mar 13, 2014 at 6:08 PM, Michael Rasmussen <mir at datanom.net> wrote:

> On Thu, 13 Mar 2014 11:45:52 -0700
> Chris Allen <ca.allen at gmail.com> wrote:
>
> > Yes.  Thanks for including the patches.  I was unaware of ZFSEdit.js as I
> > wasn't testing this on new version of pve-manager (I was using 3.1
> release).
> >
> It was also part of latest 3.1. Double-click the mouse over your
> storage specification in Datacenter->storage and the panel pops up.
> Patched panel attached.
>
> BTW. Have you made any performance measures sparse vs non-sparse and
> write cache vs no write cache?
>
> --
> Hilsen/Regards
> Michael Rasmussen
>
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> michael <at> rasmussen <dot> cc
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> mir <at> miras <dot> org
> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xE3E80917
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