Hi George, Thanks for your response. For now, all I really want is a simple way to tell if I'm getting SATA III access to my internal hard drives or still SATA II (and if I'm getting USB-3 rather than USB-2). It doesn't have to be perfect.
Gregg On Dec 15, 2013, at 2:00 PM, George N. White III <[email protected]> wrote: > Different workloads can have very different characteristics which makes I/O > benchmarks tricky. At one extreme you can have lots of small I/O requests > updating a data base where each update writes a small amount of data but also > requires updates to tables, indices, etc. Numerical simulations can write > large amounts of data as fast as the disks can take it, but will wait for the > I/O to finish before making new requests. Video capture (which these days > may involve multiple "cameras" and high resolutions) will drop data if the > disks can't keep up. > > The most useful comparison would be based on whatever elements of your real > workload are currently a bottleneck. When you make major changes to your > mass storage, there may be opportunities to improve the workflow, e.g., > running > multiple tasks in parallel, so it can be helpful to have some benchmarks for > several variations on the old workflow. At work, moving from SGI > multiprocessor systems to Mac Pro, we found that SGI I/O could handle only 2 > of our standard workload tasks, which (because we didn't want to slow down > interactive users) meant we were limited to one batch process at a time. The > Mac Pros start to bog down at around 8 tasks (using 3 disks in a stripped > configuration). > > > On Sun, Dec 15, 2013 at 1:46 PM, Dinse, Gregg (NIH/NIEHS) [V] > <[email protected]> wrote: > Hi, > > Can someone please recommend some (free?) software that would allow me to > assess read and write speeds for various disks (e.g., hard drives, SSDs, > flash drives)? > > Alternatively, are there some simple commands that I can give in the Terminal > app? At one time, I believe someone gave me such a command, but > unfortunately I have long ago forgotten it. I think the "write" part of the > test involved writing a large amount of stuff to /dev/null. > > In case anyone is interested in the background, I am hoping to use a pair of > PCIe cards to upgrade a mid-2012 Mac Pro by adding some external USB-3 ports > and some internal SATA III ports. I wanted to assess "before and after" > speeds. > > Thanks, > > Gregg > > -- > George N. White III <[email protected]> > Head of St. Margarets Bay, Nova Scotia _______________________________________________ MacOSX-talk mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-talk
