I'm getting weird fluctuating transfer speeds when copying from a workstation to Unraid cache drive (screenshot attached).
Source where I'm copying from is capable of sustaining speeds about 900MB/s, Copying from the same source to another disk attached to the workstation it will average out (~4tb folder) to about 750-900MB/s with file system overheads. I'd really like to achieve at least the same speeds when copying to unraid.
The share is set up to use cache as a primary storage, and array as secondary. Cache drive itself is a btrfs raid0 with 1 nvme pcie drive and 2 sata ssd's. I'm using raid0 since I need the cache to be at least 3TB. IF this is definitely the issue I could just buy a bigger nvme drive and use it as a single drive.
Here are some average hdparm read test results of the individual disks, that are part of cache raid0. I haven't done any write tests yet. Is it safe to write straigth to the device when its part of raid0 with dd?
/dev/nvme0n1:
Timing cached reads: 34890 MB in 1.98 seconds = 17630.33 MB/sec
Timing buffered disk reads: 4242 MB in 3.00 seconds = 1413.82 MB/sec
/dev/sdc:
Timing cached reads: 35154 MB in 1.98 seconds = 17751.61 MB/sec
Timing buffered disk reads: 1010 MB in 3.00 seconds = 336.35 MB/sec
/dev/sdb:
Timing cached reads: 36866 MB in 1.98 seconds = 18629.65 MB/sec
Timing buffered disk reads: 1002 MB in 3.00 seconds = 333.70 MB/sec
Any pointers and best practices would be really appreciated what to check next and how to troubleshoot this.
Also if this has any significance, this is a file server / project archive for my company, not a media server.
postraid-diagnostics-20240524-1321.zip