After performing the tests with iSCSI and discussing the results with a friend of mine, I was a little disappointed as it seemed that the IX4 didn’t seem to perform as well as his system. Biggest difference between my IX4 and his NAS was the use of iSCSI on the IX4 and NFS on his. The next step might be clear, test the whole set again on NFS and so I did and I can already reveal that performance was much better now and is comparable to his NAS, which made me very happy again
With the same ESX and VM configuration I reran my tests. The IX4-200D was still configured with a 2.7TB volume of which 1.5TB is configured for iSCSI, but the remaining 1.2TB is shared as NFS. I moved the test VM to this NFS volume and started iometer. (more…)
There was a good discussion on twitter on memory overcommit and the value of memory overcommit and whether you should or should not use it in production. What struck me in this was that on a subject like this, there is so much misunderstanding although there is a lot of documentation available that can explain the subtle difference between good and bad overcommit of memory.
Memory overcommit, the basics.
In short: When you assign more RAM to your VMs than available in your host.
Good memory overcommit: When you assign more RAM to your VMs than available in your host BUT never cross the line where the amount of RAM that is USED by your VMs is more than available in your host.
Bad memory overcommit: When you assign more RAM to your VMs than available in your host AND cross the line where the amount of RAM that is USED by your VMs is more than available in your host.
Eric Siebert has opened the polls for a new round of voting for the Top 20 virtualization bloggers list. I was very honored to be at 8th place in last years poll at http://vlp.vsphere-land.com/ and I hope to be in that top 20 again even though competition has stepped up. Seen some great new blogs from Frank Denneman and Hanny Michael that definitely belong in that top 20 too.
Doesn’t everybody want to brag about how fast their storage is? How they configured and tweaked for hours to squeeze the last bit of IO out of their storage? But what does it mean when someone says: “My box can do 1200 IOPS”. Is that read speed, write speed, what block size, is it a mix of reads and writes?
Recently I received an Iomega IX4-200D from Chad Sakac ( http://virtualgeek.typepad.com ) (Thank you very much Chad!!!) and I of course wanted to put it to the test and see how many IOPS the IX4 could give me. Biggest question was however: “How to test it thoroughly and in a sensible way”. (more…)
Just a few minutes ago I received the really sad tweet that Tripwire has decided to discontinue the vWire product. Tripwire has been highly successful in security and compliance and wants to focus all of their efforts on this in 2010. To read more, click here. I’m very sad to hear this news for a couple of reasons. First and all because of the consequence this has for the great team that worked for vWire. Personally I have mostly been in contact with Stephen (Steve) Beaver and Karen Hepner and I loved working with them.
Secondly I’m sad because a great product like vWire is going to stop. I’ve written a review on vWire a few months back and was really convinced about the value of vWire and the potential that was still growing. A shame to see a product like this to be discontinued. I wonder what will happen to it. (more…)
