[THIN] Re: OT: VMWare ESX 3.x Internal / DMZ networks on same physical server

Rick was quite specific of the scenarios where he consider latency - and
it wasn't purely booting - but things like pagefiles, profiles, and
printing spool areas.
 
It's for reasons like this, that whilst SAN filesystems for servers has
been prevalent for some time - given the nature of application use of
storage, and impressive caching with SAN storage, SAN booting has been
less prevalent, and some of that will come down to OS behaviour, and the
nature of the storage.
 
Neil


  _____  

        From: thin-bounce@xxxxxxxxxxxxx
[mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Steve Greenberg
        Sent: 23 February 2007 15:28
        To: thin@xxxxxxxxxxxxx
        Subject: [THIN] Re: OT: VMWare ESX 3.x Internal / DMZ networks
on same physical server
        
        

        So are you saying that SAN boot disks suffering from latency
issues? I am trying to get a clear answer here- does your OS/Application
performance suffer as a result of pure SAN booting??

        

        Steve Greenberg

        Thin Client Computing

        34522 N. Scottsdale Rd D8453

        Scottsdale, AZ 85262

        (602) 432-8649

        www.thinclient.net

        steveg@xxxxxxxxxxxxxx

        

        
  _____  


        From: thin-bounce@xxxxxxxxxxxxx
[mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Braebaum, Neil
        Sent: Friday, February 23, 2007 8:14 AM
        To: thin@xxxxxxxxxxxxx
        Subject: [THIN] Re: OT: VMWare ESX 3.x Internal / DMZ networks
on same physical server

        

        Just to point out the subtle, yet poignant, difference between
throughput and latency...

        

        Neil

                

                
  _____  


                From: thin-bounce@xxxxxxxxxxxxx
[mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Steve Greenberg
                Sent: 23 February 2007 15:11
                To: thin@xxxxxxxxxxxxx
                Subject: [THIN] Re: OT: VMWare ESX 3.x Internal / DMZ
networks on same physical server

                Rick,

                This is very interesting. I was under the impression
that SAN booted hardware servers would be faster than local disk given
the 2GB throughput of fiber channel and the efficiency of the SAN
platform (spanning many spindles). Are you saying it is actually
slower??

                Steve Greenberg

                Thin Client Computing

                34522 N. Scottsdale Rd D8453

                Scottsdale, AZ 85262

                (602) 432-8649

                www.thinclient.net

                steveg@xxxxxxxxxxxxxx

                
                
  _____  


                From: thin-bounce@xxxxxxxxxxxxx
[mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Rick Mack
                Sent: Friday, February 23, 2007 3:37 AM
                To: thin@xxxxxxxxxxxxx
                Subject: [THIN] Re: OT: VMWare ESX 3.x Internal / DMZ
networks on same physical server

                Hi Steve,

                VMs aside, there are still a couple of significant areas
where SAN disks just don't hack it as a system disk. 

                The first is latency which can be 4-5 times worse on a
SAN "disk" (overhead of fabric switch and other infrastructure) compared
to local disks. I know that DR etc is a lot easier with SAN disks than
local hard disks, but if you decide to go SAN boot and still want want
real performance then you'd better at least consider using the local
hard disks for paging, spooling and user profiles. 

                The second issue is price. Even with 72 GB disks where
most of the disk space is wasted, SAN disk space still costs quite a bit
more than RAID mirrored local drives.

                I have a suspicion that there will be a time in the near
future when people will start realising that that VMWare isn't nearly as
cost effective as everyone argues. Please don't get me wrong, I love the
idea of VMWare and just wouldn't do without it. It's just that VMWare
isn't really about saving money once we get away from a development
environment. 

                And until we can overcome disk and network i/o
bottlenecks, having more CPU power to play with just isn't all that
critical. Of course there are things like Vista/Longhorn's flash drive
read/write caching that even things up a bit but what we really need is
the next generation of hard disks that have obscenely large on-board
caches. That'll let them run at close to the interface speeds (eg up to
6 Gb per disk on SASI). 

                regards,

                Rick

                On 2/23/07, Steve Greenberg <steveg@xxxxxxxxxxxxxx>
wrote:

                        Nice! This is one of those mind set changes that
we periodically have to go through. I am going through one right now
with the idea of booting servers off the SAN, in the old days this was
flaky but I have to update my thinking and accept that it works and is
trustworthy! 

        



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