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The Kilo-Client has ventured into several new territories and has encountered surprises that required adjustments. One of the biggest surprises was how the storage grid is used. Initially, it was envisioned that many nodes performing the same task would be a primary use of the Kilo-Client. Instead, "most of our engineers are using a single node, such as a Linux server, testing 50 different storage controllers," says Ferguson.
Assigning an adequate number of disk drives to boot all 224 blades in a "hive" took a while to get right. "Initially, we started with 30 drives per 'hive,' which worked great for booting; but once the applications started to run, spindles were 100% busy, causing excessive latency," explains Brown. The problem was remedied by adjusting the number of spindles per "hive" from 30 to 42, which lowered drive utilization to 70%.
The team was in for another surprise when engineering started VMware tests with 224 servers in a "hive" running five virtual servers per node. Disk utilization went through the roof and the number of disks had to be increased from 42 to 96, requiring four additional disk shelves.
Another lesson learned relates to FC SAN booting. "If someone wants to run tests over Fibre Channel, it's not optimal that these servers are SAN booted via Fibre Channel," says Ferguson. "It would be better to either boot these servers via NFS or iSCSI, and let [the] FC ports be available for FC testing."
The Kilo-Client project showcases how SAN booting and thinly provisioned snapshots can be used in a storage grid for rapid provisioning, simplified storage management and huge disk space savings. These tasks are central to any storage environment and certainly don't depend on NetApp products to implement. As SANs take on more and more ports, it becomes increasingly important to find new ways to reduce management interventions, test new products, and move and protect data.
This was first published in October 2007