[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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