Incremental cost from 24 to 32 or even 48 GB of RAM is going to be fairly low. More RAM reduces IO too. Might as well get it while you can.
I agree that IO could be an issue. That said, 6 - 8 SATA drives RAID10 is going to give you 300 - 400 IOPS which is a decent amount. That said, 6 -8 15K RPM SAS drives will buy you 700 - 900 IOPS so big delta there. Thanks, Brian Desmond [email protected] w - 312.625.1438 | c - 312.731.3132 -----Original Message----- From: Ken Schaefer [mailto:[email protected]] Sent: Sunday, December 04, 2011 7:47 PM To: NT System Admin Issues Subject: RE: Virtualization - Sizing, hard disk config You could look at the Microsoft MAP tool to get more of a feel of how your resources are being used today. Secondly, I think your bottleneck will be I/O. You can get heaps of cores and RAM fairly easily in any mid-level box. You're looking at running 5 VMs on about 4 disks - that's ~1 disk/VM. Granted it's not quite that simple - different VMs will write at different times. Print: 2GB RAM DC/DNS/DHCP: 2GB RAM File: 4GB RAM Exchange 4-8GB RAM Other: 4GB Total: 24+ GB of RAM and you should be fine. Cheers Ken -----Original Message----- From: Ben Scott [mailto:[email protected]] Sent: Saturday, 3 December 2011 4:24 AM To: NT System Admin Issues Subject: Re: Virtualization - Sizing, hard disk config On Fri, Dec 2, 2011 at 2:34 PM, Paul Hutchings <[email protected]> wrote: > Spend some time logging your IOPS so you know what you need to support. Since we're moving to Win 2008R2 and Exchange 2010 (I forgot to mention that), and virtualization on top of that, I haven't been putting a lot of thought towards benchmarking our current systems. I was assuming what we have now would not translate to what we're going to get. > Don't skimp on RAM - that is where you will usually start to see a > bottleneck long before you do CPU and disk (assuming you know what IOPS you > need and spec accordingly). Not planning on skimping on it. The question I have is -- *what is enough*. 16 GB? 24? 32? > Ideally, buy two boxes, with one box all your eggs are in one basket ... I am aware of this. As you say, it's what we have now. It's relatively cheap for us to get a service contract to cover hardware failures to the 2HR mark. Two boxes doubles the cost. Or they're not powerful enough to handle the load, in which case, you're not really getting redundancy. > Don't rule out SAN storage. People think SAN and think expensive > hardware - there are a number of low cost (relative) software SANs > that let you take DAS storage and pool it and cluster it. Cheapest decent stuff I have found is still a drastic price increase over DAS, even with just a single server. I am aware of the benefits of SANs. For this organization, at this time, they don't justify the cost. > Backup - don't overlook it. Haven't. Planned for. :) But thanks for checking. :) -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
