On Oct 4, 2012, at 1:33 PM, "Schweiss, Chip" <c...@innovates.com> wrote:

> Again thanks for the input and clarifications.
> I would like to clarify the numbers I was talking about with ZiL performance 
> specs I was seeing talked about on other forums.   Right now I'm getting 
> streaming performance of sync writes at about 1 Gbit/S.   My target is closer 
> to 10Gbit/S.   If I get to build it this system, it will house a decent size 
> VMware NFS storage w/ 200+ VMs, which will be dual connected via 10Gbe.   
> This is all medical imaging research.  We move data around by the TB and fast 
> streaming is imperative.  
> On the system I've been testing with is 10Gbe connected and I have about 50 
> VMs running very happily, and haven't yet found my random I/O limit. However 
> every time, I storage vMotion a handful of additional VMs, the ZIL seems to 
> max out it's writing speed to the SSDs and random I/O also suffers.   With 
> out the SSD ZIL, random I/O is very poor.   I will be doing some testing with 
> sync=off, tomorrow and see how things perform.
> If anyone can testify to a ZIL device(s) that can keep up with 10GBe or more 
> streaming synchronous writes please let me know.  

Quick datapoint, with qty 3 ZeusRAMs as striped slog, we could push 1.3 
GBytes/sec of 
storage vmotion on a relatively modest system. To sustain that sort of thing 
often requires
full system-level tuning and proper systems engineering design. Fortunately, 
tend to not do storage vmotion on a continuous basis.
 -- richard



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