Cost of Server RAM
Wow, 8 GB DIMMs are awefully expensive! This was discovered recently while pricing a 2 RU (rack unit) server from a well known vendor. The server contained 4 DIMM slots, and when equipped with 4 x 4 GB DIMMs came out at about AUD20k. Not too bad for a fast dual Xeon quad-core box with 16 GB of RAM. However, changing the RAM to 4 x 8 GB DIMMs increased the price to over AUD60k. Actually, the RAM alone cost about AUD50k. Youch!!!
So, it’s cheaper to buy two servers from this vendor with 16 GB of RAM each than to buy one server with 32 GB of RAM. Thinking that this was a blatant rip-off, servers with similar specifications were priced from other well known vendors. The massive price differential between 16 GB and 32 GB versions were almost identical for all vendors. So, 8 GB DIMMs really are expensive.
Now, you might be asking: Why in the world do you need so much RAM? Server virtualisation. Each of these physical servers would be running quite a few virtual servers, including applications like SQL Server and ArcGIS Server. Having enough RAM becomes very important for performance reasons, but luckily 16 GB per dual processor server is probably enough.
They could probably have gone a bit longer, but we're moving to VMWare 3, and it's easier to transition than to upgrade all at once.
Jason Birch — 2 March 2007, 11:24
It's great for dev/test, but I'd steer clear of VM's for production.
Dave
Dave — 2 March 2007, 16:28
Do you have any details on where the bottleneck was when running on VMs? CPU time, network, RAM/disk swapping, etc.
I understand that there will be some overhead, and it depends what else is running on the same physical server, but ~30% sounds quite high.
Andrew
Andrew Hallam — 2 March 2007, 18:08
When I attended the ESRI System Design Architecture class last November, one student was considering virtualizing their production ArcGIS Server system, and the instructor cautioned him, and mentioned the 30% hit. They did not have any published numbers, but apparently this was what they had experienced in their testing lab. Shoot an email to sihelp@esri.com (system integration group) asking for information related to ArcGIS Server performance in a virtualized environment, and they should be able to provide you more details.
Cheers,
Dave
Dave — 2 March 2007, 21:41
Has anyone actually taken the plunge and run ArcGIS on a server using VMWare? If so, how did it work?
Was there a dramatic performance issue or did it work well?
Please advise. We're considering this approach and are looking for success stories to boost our confidence.
Thanks!
Mike
Mike — 4 July 2007, 15:25