File Speed

[sloppy1969]

What kinds of SMB file transfer speed in windows with 10gb networking and good SSD cache disk should I be able to achieve?

[JorgeB]

Depends mostly on the hardware used, 1GB/s is possible with fast enough NVMe devices.

[sloppy1969]

So Im able to achieve about 1GB/s for about half the transfer "lets say for a 5-10Gb file", then it drops to about 200-300Mb/s, then tanks to about 20-30 Mb/s. Im not sure why. Im not sure what my problem is. Is this a parity issue or my SSD cant keep up ? How would I trouble shoot this? 

[JorgeB]

2 minutes ago, sloppy1969 said:

So Im able to achieve about 1GB/s for about half the transfer "lets say for a 5-10Gb file",

That's while it's being cached to RAM, if it drops after that your SSD can't keep up, even the fastest normal SATA SSD (not NMVe) will usually max out at around 300MB/s, slower TLC based SSD can drop to <100MB/s.

[sloppy1969]

Does it not cache the entire file in ram then write to disk ? Would raiding "0" the SSDs be any better ? 

 

[testdasi]

13 minutes ago, sloppy1969 said:

Does it not cache the entire file in ram then write to disk ? Would raiding "0" the SSDs be any better ? 

 

You are asking rather simple questions with no details for a complicated issue.

 

What are you copying between (over network? VM to VM? VM to array? VM to cache? cache to cache? etc)? What is your share setting? What is your SSD? How big are the files? How many files?

[JorgeB]

18 minutes ago, sloppy1969 said:

Does it not cache the entire file in ram then write to disk ?

By default 20% free RAM is used for write cache.

[sloppy1969]

1 minute ago, johnnie.black said:

By default 20% free RAM is used for write cache.

Ok, I assumed it would cache more, is this a commonly changed setting or is that bad practice?  

[JorgeB]

In my experience it's only worth increasing if you do mainly do small transfers that will always (or mostly) fit in cache and can wait for the data flush before starting another transfer, or the data flush will be slower than before.

[sloppy1969]

6 minutes ago, johnnie.black said:

In my experience it's only worth increasing if you do mainly do small transfers that will always (or mostly) fit in cache and can wait for the data flush before starting another transfer, or the data flush will be slower than before.

Ill give it a test and see, its mostly video projects I move off my desk top into unriad, I was reading a post you tested this in. 

 

Is this the command you used "sysctl vm.dirty_ratio=90"?

Where is the file on the flash  "flash/config/disk.cfg"?

 

 

Edited November 20, 2019 by sloppy1969

[JorgeB]

3 minutes ago, sloppy1969 said:

Is this the command you used "sysctl vm.dirty_ratio=90"?

Yes, but that's not on disk.cfg, you can create a script with the user scripts plugin and have it run at array start.

[sloppy1969]

20 minutes ago, johnnie.black said:

Yes, but that's not on disk.cfg, you can create a script with the user scripts plugin and have it run at array start.

Thanks for all the help, Ill test it out later today.