[postgis-users] VMWare and PostGIS

[Stephen V. Mather]

Hi Paul,
       Fortunately I'm not cursed with enough budget to worry about what the Ducati equivalent would be... .  :)
       The VMWare host in question is dedicated to GIS applications, so the virtualization layer probably isn't the primary issue, it sounds like.  Oh well.  Time to get some fast disks... .

Steve



[http://sig.cmparks.net/cmp-ms-90x122.png] Stephen V. Mather
GIS Manager
(216) 635-3243 (Work)
clevelandmetroparks.com<http://www.clemetparks.com>



________________________________
From: postgis-users-bounces at lists.osgeo.org [postgis-users-bounces at lists.osgeo.org] on behalf of Paul Ramsey [pramsey at opengeo.org]
Sent: Saturday, January 12, 2013 8:18 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] VMWare and PostGIS

The most important thing is to figure out where your "fast enough" place is, and not get too hung up on the "fastest" thing. If we wanted to be fastest, we'd all drive Ducatis to work, but clearly fast enough works for most of us.

The main problem with AWS is not the virtualization, it's the shared tenancy. It's possible for other tenants to saturate the I/O at unpredictable times, taking it from acceptable to non-existent, with no predicability. This will be true, though to a lesser extent, with private virtual environments, like shared VMWare hosts run by your IT department.  ("To a lesser extent" because AWS storage is network mounted, so everything the host does with I/O has to push out through a network pipe. Your IT department VMWare host, on the other hand, will at least have separate network and storage I/O channels.)

I have heard of, but never seen, VMWare hosts that attach directly to SAN storage over iSCSI. So the host is virtual, but the storage is at full SAN speed. A "best of both worlds" situation, but with the added cost of SAN infrastructure.

P.


On Sat, Jan 12, 2013 at 4:36 PM, Stephen V. Mather <svm at clevelandmetroparks.com<mailto:svm at clevelandmetroparks.com>> wrote:
Hi All,
I should have asked this a long time ago regarding performance... .  So the classic storage solution (AFAIK) for a spatial database is RAID 10 for maximum read and write speed.  I have a RAID 10 running under a virtualization layer (VMWare in this case) and my sustained read speeds are in the 1Gbps range.  The hardware is oldish, but they are 10k SAS drives, so I would expect something a bit faster.
        To the question-- I know virtualization makes a (not-so-good) difference in performance running spatial databases on e.g. Amazon EC2 instances.  I assume this penalty is paid even for dedicated private clouds.  What is the consensus/experience with virtualization?  For my next machine, should I keep it to bare metal for the PostGIS portion?

Thanks in advance,
Best,
Steve

[http://sig.cmparks.net/cmp-ms-90x122.png] Stephen V. Mather
GIS Manager
(216) 635-3243<tel:%28216%29%20635-3243> (Work)
clevelandmetroparks.com<http://www.clemetparks.com>


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