Since recently each scrub on my RaidZ2 stalls a little bit below 85% completion.
The scan rate drops from about 150M/s to about 64K/s, the issuing rate goes to nil.
Dedup and compression are active, ashift is 12.
The RaidZ2 comprises 10 4TB WD RED (CMR) connected via a HPE 240 HBA and a 500GB WD Black SSD as L2ARC; the System has 64GB of RAM and runs Ubuntu 20.04.
I initialized the RaidZ2 some weeks ago and transfered a lot of very important research data for my PhD on it (this data does highly benefit from dedup). After this transfer a scrub did go swiftly and completed ok.
Next I transfered my personal photo library to the RaidZ2 - then the problems started - since then all scrubs stall at about 85%
I checked the SMART reports from all drives and found no issues. I even checked the HBA but found no problems either.
The storage pool is reported as online with no errors.
pool_10x4TB 36,4T 17,9T 18,4T - - 53% 49% 7.47x ONLINE -
Yet being not able to scrub I ask:
Is my data still intact??
What does it mean for a ZFS pool to be online when scrubbing does not succeed?
Could therebe a bug in the scrubbing routine?
Or is this a sign of bad things to happen to my Raidz2 soon?
What can I do? What shall I do?
Thank you very much!