Kash posted the following as a reply to a Tom Treadway post. Since out of respect I won’t continue Tom’s posts I’ve made a new post in regard to this …

I took 7 SATA 300 drives of varying sizes (2 x 640GB, 4 x 500GB, 1 x 1TB) from different manufactures (WD 640, Samsung 640, Maxtor 500, 3 x Seagate 500, and I can’t remember the 1TB). In a Linux 2.6.29 machine with 2 x Intel QX9775s @ 3.0GHz, 8GB of RAM (4 x 2GB @ 1066) and an Intel DX5400 motherboard, I set up an LVM stripe over all of these devices. It didn’t allow the full size to be used (it defaulted to 7 x 500GB drives), but when I benchmarked the array, it saturated the PCI-E 2.0 bus. Yes. The drives pushed out 500MB/s constantly. I’m sure if I had PCI-E 3.0 (not out yet) it would have seen even higher speeds, considering that each drive (save for the Maxtor 500) pushes about 110-120MB/s on its own.

Kash … I need a lot more information before going to much further with this one. Firstly, need to know what card you are using. Since the PCIe specification doesn’t have a 500MB/sec limit - it jumps straight from 256 for x1 to 1GB/sec for x4, I’m not sure I see where your limitation is.

Since most of our cards are PCIe x8 they have a realistic throughput of 1800MB/sec (give or take a few mb). What sort of benchmark you are using, and whether it’s streaming reads or writes or random reads or writes will have a major impact on performance.

We have customers attaining well over 1000Mb/sec streaming read speeds from SATA drives these days, so there’s plenty of performance left for you to go yet.

Ciao
Neil

This entry was posted on Tuesday, June 2nd, 2009 and is filed under General, Storage Applications, Platforms, Storage Interconnects & RAID, Storage Management, Application Environments, Advisor - Neil. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.