IOMeter v2006.07.27 – IOps
Iometer is an I/O subsystem measurement and characterization tool for single and clustered systems. It was originally developed by the Intel Corporation and announced at the Intel Developers Forum (IDF) on February 17, 1998 – since then it got wide spread within the industry.
Meanwhile Intel has discontinued to work on Iometer and it was given to the Open Source Development Lab (OSDL). In November 2001, a project was registered at SourceForge.net and an initial drop was provided. Since the relaunch in February 2003, the project is driven by an international group of individuals who are continuesly improving, porting and extend the product.
Different things happened when we tested our RAID pair. They excelled in the pure random reads of our web server test, even beating the X25-M G2 TRIM model. This was because the G2 is saturating the single SATA channel at its plateau. In the file server test, the duo almost perfectly matched the 80GB G1. Results became weaker and more inconsistent as we entered the write-heavy database and workstation tests. This is actually an issue I’ve noted with SSD’s RAIDed under an ICH. Either the ICH or its driver seems to amplify what would normally be small delays encountered as each SSD services a given write request. I’ve noted this amplification gets even worse as you add more SSD’s to the RAID. I’m still investigating this (as I have been for months now), and continue to work with Intel to try to get to the bottom of it. What I want you to take away from the above is that the lack of scaling for mixed read+write tests under a RAIDed pair of SSD’s is not necessarily the fault of the drives.