Slow file transfer, but not always

[etorix]

@Protopia

Green drives are often unsuitable in other ways i.e. they are not designed to report errors promptly but rather to keep trying for excessive time when an error occurs - and this makes them better for non-redundant desktop drives, but unsuitable for redundant vDevs where an early error is preferable so that ZFS can use the redundancy to present valid data quickly.

This might be fixed by setting a suitable TLER vallue.

Checking for TLER, ERC, etc. support on a drive

But the pool has several flaws.
sda Barracuda CMR 2 TB — OK
sdb Barracuda Green 2 TB — check TLER (and other drives as well)
sdc Barracuda SMR 2 TB — should be replaced as soon as possible
sdd Barracuda Green 2 TB — 10.5k reallocated sectors, this drive is degrading, and this is another possible cause of slowdowns; replace immediately, RMA if possible