[Support] File transfer speed dropped after 30 seconds

[bohaman]

Hello,

 

I am running into problem where my transfer speed doesn't get full speed after for about 30 seconds or so.

 

I've tried to resolve it by some other post by disabling bond and bridge and connect directly from unraid 10gbe but it seems the problem still persist.

 

I've attached my diagnostic log as well.

 

 

tower-diagnostics-20231008-0936.zip

[MAM59]

The usual reason for such a drop is that an envolved disk cannot keep up with the speed and buffers run out.

Need some time to flush, then transfer resumes. Nothing harmed.

 

If you use "normal" (spinning) disks, this behaviour is to be expected, they cannot keep up on reading or writing with a 10G link. The pauses happen almost instantly (after RAM buffer is full)

If its a SATA SSD, it works a bit longer and the pauses are shorter (faster drive), but it will happen too.

NVME SSDs are tricky. They claim they can keep up, but many of them are cheating. They use internal cache and once this is full, the pauses happen too with them. Only few drives (usually in the higher price regions) are able to "eat"  a 100Gig+ File without waving the white flag.

 

If you write to the UNRAID array without a cache, write time is even doubled because parity drive(s) need to be written too. So pauses happen sooner and are longer.