There are plenty of benchmarking tools available but storage professionals mostly use IOmeter. Unfortunately IOmeter is a little tricky to use. You really need to read the user manual first. I have frequently seen users trying to run IOmeter tests without success. Being human, most of us hate to read the manual and with IOmeter this can lead to problems. I hope this short post will help you to get the wanted results. First off, [...]

I am not kidding. We were getting queries about the performance of our latest DSS V6 build 4786. So I needed to quickly set up a performance benchmark. It took me about 5 minutes to set one up with a Fibre Channel volume connected to a VMware ESXi 4.1.0 host. My test server has a 4Gb dual-port FC HBA, so in order to get maximum performance I configured a round-robin Multipath. Then I ran IOmeter [...]

From time to time some meticulous customer will ask us how come a fresh formatted hard disk or RAID array volume is smaller than the nominal capacity.  For example when you format a 1TB hard disk the resulting drive appears to have 931 GB even though the hard disk label claims 1000GB. Where is the “missing” 69GB? The problem is much more pronounced if someone formats a 16TB RAID volume and instead of the expected [...]

There is  plenty of talk about Bonding and Multipath IO, but it is very difficult to get solid information about either one. Typically what documentation can be found is very bulky and the most important practical questions go unanswered. As a result the following questions are often heard: When should I use bonding and when should I use multipath? I was expecting better throughput with bonding, why am I not seeing this? My RAID array [...]