Speeding up rsync

[joe_schmo]

Am about to upgrade some drives in my readynas and was wondering if there was a way to speed up the process.

I had read that speed_limit_max is the throughput ceiling that applies when there is no other activity, limiting the top speed to 200 KB/sec.

Is this changable/supported? Or is there any other way?

[JennC]

Hello joe_schmo,

Have you tried firmware 6.8.0?

Regards,

[joe_schmo]

hi JennC -

Sorry, but what would that solve?  I don't see anything in the release notes that would allow me to chagne the dev.raid.speed_limit_max value.

Also, I am pretty sure I can't upgrade the formware while resyncing...

[Skywalker]

It's 200 MB/sec, not 200 KB/sec.  If you're not using all SSDs, then this limit will probably never be hit anyway.  If you are using all SSDs, then the limit likely will be hit; but it's there for a reason, so the resync doesn't eat up all the CPU cycles doing parity calculation.

[joe_schmo]

If it was 200MB/sec, it wouldn't take 65 hours to rsync an 8TB drive.

If I do watch cat /proc/mdstat it shows:  speed=25780K/sec

[Skywalker]

Perfect, then that confirms that changing dev.raid.speed_limit_max will make no difference for you.  It sounds like it's probably doing a reshape rather than a resync.  Reshapes involve a more work than resyncs, and are thus much slower.  The 25 MB/sec you are seeing sounds about right.