I recently upgraded from 1.7.2 to 1.9.4. Though the upgraded went smoothly, I’ve been experiencing strange slow downs, or hiccups, while writing files.
Using High Sierra, I’m running ZFS2 with 7 WD 4GB Reds, connected via internal SATA controllers (Marvell 88SE9215). During writes, network or internal SSDs, I’ll be cruising along when things will just slow down to just a few KB/s. After a several seconds, sometimes +10 seconds, things will pick right back up. During large writes, this cycle can occur many times.
Zpool status shows everything is fine. And a scrub was uneventful.
Thinking it’s possibly a failing drive, I ran GSmartControl and discovered one bad sector on one drive. I’ve been monitoring the drive for a couple of weeks, and the bad sector count has remained the same. The “Overall Health Self-Assessment Test” reads “Passed.” Running a "Short Self-Test" reports back “Completed with read failure 10%”.
I do have a replacement drive at the ready, but I don’t want to unnecessarily replace the questionable drive.
So my question is, would one bad sector explain my write hiccups?