Advice: HA Storage Appliance for Postgres

Tue Aug 16 08:49:14 PDT 2005

As a heavy user of NetApp on DBs via FC and iSCSI, they are the way to
go if you don't have the bandwidth to manage the storage on a dedicated
basis + the software uplifts that they offer have a lot of value
(SnapMirror for DR, FlexCone for developer copies of DBs, etc)

I highly recommend them -- they are far more an "engineering/admin"
company with lots of information available via their website and anytime
I've called their techsupport they have clue.  Their AutoSupport system
that creates cases & auto dispatches parts for things like drive
failures is also a huge benefit.  Others will tell you they have
autosupport, but the dispatch parts piece is usually not there.

Their CIFS/NFS stuff also rocks.

It isn't the cheapest, but well worth it IMO.

Cheers,
Dave

----
David Smith <dsmith at financialengines.com>
Voice: 650-565-7750 Fax: 650-565-4905 

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-----Original Message-----
From: owner-baylisa at baylisa.org [mailto:owner-baylisa at baylisa.org] On
Behalf Of John Martinez
Sent: Tuesday, August 16, 2005 8:24 AM
To: Danny Howard
Cc: baylisa at baylisa.org
Subject: Re: Advice: HA Storage Appliance for Postgres

On Aug 15, 2005, at 4:44 PM, Danny Howard wrote:

> ...
>
> Can someone offer a bit of advice here:
> - Am I thinking the right way?
>
>

Somewhat, although I would avoid using SCSI in preference to Fibre
Channel, that is if you want to connect multiple hosts to the same
array.

> - I think I want to avoid anything called "SAN" right?
>
>

Note necessarily. But just because I say "Fibre Channel", doesn't mean
I'm saying SAN. You can direct-attach Fibre Channel devices to your host
if you have Fibre Channel HBAs. If you want to connect multiple hosts, a
SAN is the easiest way to do so, but can get expensive In the end, your
host will see these drives as SCSI.  
Confused yet? Don't worry, I was somewhat confused at first, too.

> - These days, is SATA versus SCSI versus fiber versus copper connects
>   important?
>
>

You're mixing several things together. SATA versus SCSI are drive types.
Fiber Channel drives are a third type of drive, having nothing to do
with fiber optic cables (yet). You can find arrays with the three types
of drives that have fiber connections (most common) and some that have
copper connections.

There are lots of high-performance SATA disks out there now, with
comparable performance to SCSI and Fibre Channel. Although be careful of
write performance. Once you pick some vendors to look at, see about what
tests they've done given typical RAID set ups. Even go so far as
requesting an evaluation unit and do your own testing.

> - Anyone have a particular vendor they like?  There was a place in
>   Soquel that was very helpful for me back in 2000 but I can not seem 
> to
>   find them any more ... HP?  IBM?  Sun?  A local integrator?  (ASA
>   don't seem to do this stuff.)
>
>

Depends on your budget. These things can get pretty expensive. We tend
to gravitate towards Hitachi.

> - Is an NFS/NetApp solution viable?
>
>

Depends on what you're trying to do. Some people like to use NFS
(NetApp) for database hosting, I personally don't like NFS for that type
of application, but it is easy to set up. From what I understand, you
can get a NetApp with Fibre Channel interfaces now and use it like a
Fibre Channel array.

> - Do smaller disks provide better performance in RAID contexts?
>
>

That's the thought, anyway. I find that the number of spindles has more
to do with performance (most Fibre Channel disks being 10k and 15k RPM),
although you have to be careful of the reliability factor with too many
spindles in your RAID set.

The issue you may run into is support for your OS. I don't use FreeBSD
for high-end storage (we use Solaris). You'll find things get
complicated with multipathing and how to handle that on your OS.  
Storage vendors can get picky at that point. I'm not saying that vendors
won't support FreeBSD. I'm just saying we found Solaris to be
traditionally better supported, although Linux is just as supported
these days.

Good luck,
-john