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! ***************************************************************************** This email and its attachments are confidential and are intended for the above named recipient only. If this has come to you in error, please notify the sender immediately and delete this email from your system. You must take no action based on this, nor must you copy or disclose it or any part of its contents to any person or organisation. Statements and opinions contained in this email may not necessarily represent those of Littlewoods Shop Direct Group Limited or its subsidiaries. Please note that email communications may be monitored. 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