Yes, you should always use a power of two of devices for a stripe.
For example, two, four, eight, 16, 32, …
1 Like
The latest result, 10651 seconds for one plot, using 4xSAS raid 0 as temp1 and a ramdrive as temp 2, allocated 32 threads but processor was hardly working at all.
So this does add weight to the idea this is all limited by disk speed really. My SAS drives are connected to a Dell H710 Mini.
So I tried just copying some files from one drive to another.
From SAS to SAS it never goes above 160Mb/sec.
From one Ramdrive (ImDisk) to the other it manages 600 MB/sec.
Is this about right?
My farmer with single Xeon E3-1230L 4C/8T @ 2.6 GHz with 4x 450GB 15K SAS drives in raid0 as temp1 & temp2 is always limited by CPU as i have low I/O wait times and high CPU load.
This results in 8200 seconds in average for one plot.
So there is something really wrong with your setup…
What SAS drives are you using? 10K or 15K?
Are you on windows or on linux? Windows is very bad with ram drives on madmax plotter… See Mad Max Plotter, some test results, some general info - #343 by djjaeger82
10K drives
windows, using ImDisk.
Next stop linux.
How fast can you sustain a file copy from your quad sas raid 0?
Something is wrong with your setup. I have a 1 TB 980 pro that I use as both tmp1 and tmp2 and a 5900x, and I get 35.8 minutes per plot for k32.
Yes, I am starting to think so. It’s not the processor as silverbench gives it 50000 and a 3990 threadripper gets about 140000 this sounds about right to me.
So it is either the ram is very slow, or the disks, or the disk controller.
I get a fairly consisitent sustain 160MB/sec from the disks, and 600 MB/sec from the Ram by just copying a plot in windows and seeing the transfer rate. How does this compare to your systems?
My 4x 15K SAS drives are getting a sequential throughput of 579 MB/s, but I doubt that sequential write speed is that important. A single 15K SAS drive is getting a sequential throughput of about 168 MB/s which isn’t much more than my farming drives with 7.2K rpm.
I think your ram drive implementation (windows) is very slow and on your hdds probably you have a bad filesystem in use… exFAT is a performant filesystem, NTFS is very bad!
Thanks, I will reformat to exfat, that’s a simple thing to try. I will update my perc firmware too.
I am downloading Ubuntu, I will see if this makes a big difference.
This is running two MM processes:
Switched to exfat on all temp drives and ramdrives, I then started running in the 10-11000 second range with two processes staggered.
Then I switched the RAM to max performance in the BIOS, enabled processor turbo mode, switched to using OSFmount for ramdrive, updated my Perc710 mini firmware and installed a whole bunch of driver updates.
In windows, I just did a plot in 6953 seconds with a second one started after 10 minutes or so.
So now I think I am in the ballpark. Interestingly I am using 64 buckets on one process which is turning in 6000-7000 second plots, the other process is using 512 buckets and doing 12500 seconds. Might try 32…