[gpfsug-discuss] GPFS for DBs..MySQL, PGSQL, etc; How about VMware?

[Zachary Giles]

Frank, Edward, David, Christoph,
The Oracle 12c certified with GPFS 4.1 looks like they only mention
AIX with GPFS.. though it could apply to Linux too I believe. There's
no tuning info in it...
I do see the DB2 and SAS whitepapers. I've read those over and over
trying to tune for Oracle and other things. They're OK, but I'm not
really interested in DB2 (Though I'm sure lots of IBM people are.. ),
and they also don't seem to say or "Show" much of tuning over
different block sizes, direct writes vs not, read pattersn, data
integrity, etc.  They're still valuable though.

I _did_ find moderate info on Oracle, Though it is fairly scattered.
I'm doing a bunch of testing with Oracle right now and it's .. finicky
.. with GPFS. Yes it works, and there are comments on data integrity
here and there about Direct IO and ASync IO bypassing cache.. Oracle
has latches, etc. So, seems like you could assume the data is good on
GPFS.  There's very little in terms of tuning. So far, it seems
unhappy with large block sizes, even though it is recommended, but
they're calling "512KB" large, so it's all from more than several
years ago.
Places to look: IBM GPFS 4.1 docs.. there's a section; Oracle 11g
"Integration" docs.. probably still applies for 12, though it's
removed; Random Blogs

What I can't find, and am most interested in, is, info on MySQL and PostgreSQL.
I see little blogs here and there saying it will work, and _some_
engines support DirectIO.. but I'm wondering if MySQL will Do The
Right Thing (tm) and ensure writes are written and data is good over
this "remote" file system. I worry that if it goes offline or we have
waiters that it won't make MySQL very happy and there will be data
loss. There's already enough stories about MySQL data loss online. I'm
wondering if GPFS "feels" like a local disk enough to MySQL that it
won't fail in the way NFS does for MySQL. I'm guessing the answer is
that with some engines like InnoDB and direct io turned on, it'll be
fine and for others it will be whatever you get.. but that's not very
reassuring.
PostgreSQL seems to have even less info.

Dean,
I'll look in to those. Thanks. Are those all in 4.1 and in the new
protocol servers? Does HAWC work when the client is over NFS? I assume
the server would take care of it.. Haven't read much yet.

Christoph,
Looks like that RDM is only for ESX (the older linux-based
hypervisor), not ESXi. AFAIK there's no GPFS client that can run on
ESXi yet, so the only options are remote mounting GPFS via NFS on the
Hypervisor to store the VMs.
Or, inside the VM, but that's not what I want.

Simon,
I'm talking about on the hypervisor. Looking for a way to use GPFS to
store VMs instead of standing up a SAN, but want it to be safe and
consistent. Thus my worry about backing VM disks by NFS backed by
GPFS...

-Zach


On Fri, Sep 4, 2015 at 2:57 AM, Simon Thompson (Research Computing -
IT Services) <S.J.Thompson at bham.ac.uk> wrote:
> When you say VMware, do you mean to the hypervisor or vms? Running vms can of course be gpfs clients.
>
> Protocol servers use nfs ganesha server, but I've only looked at smb support.
>
> Simon
> ________________________________________
> From: gpfsug-discuss-bounces at gpfsug.org [gpfsug-discuss-bounces at gpfsug.org] on behalf of Zachary Giles [zgiles at gmail.com]
> Sent: 03 September 2015 15:59
> To: gpfsug main discussion list
> Subject: [gpfsug-discuss] GPFS for DBs..MySQL, PGSQL, etc; How about VMware?
>
> On that same note...
> How about VMware?
> Obviously I guess really the only way would be via NFS export.. which
> cNFS was .. not the best at (my opinion). Maybe Protocol Servers are
> better? Maybe also a "don't do it"?
>
> Thanks,
> -Zach
>
>
> --
> Zach Giles
> zgiles at gmail.com
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-- 
Zach Giles
zgiles at gmail.com