Just a data point on SMART value 22 (Helium_Level)
I have a 10x8TB zpool filled with WD easystore red/white disks.
All the disks are almost 5 years old now (disks have around 40,000-41,000 hours) and the pool is about 80% full.
For the past year I have noticed the Helium_Level attribute decreasing on one of the disks.
About 6 months ago it crossed the threshold of 25 (25% since it started at 100?) where it is considered FAILING_NOW.
I have been continuing to use it in the pool daily since then and currently it is down to a value of 7.
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
22 Helium_Level 0x0023 007 007 025 Pre-fail Always FAILING_NOW 13
The disk is still seeming to operate like normal despite having been below the 25 threshold for about 6 months so far and under 10 for several weeks now even.
I have seen 0 errors on the disk in the zpool status or anything in the kernel logs.
I also do monthly scrubs so this disk has been scrubbed more than a few times well under 25 Helium_Level.
I will continue to monitor and use the disk until it actually shows signs of data failure in the zpool.
Just thought you guys may find this info interesting or useful.
EDIT NOTES ADDED
All other 9 disks are still showing 100/100 Helium_Level.
Temps have historically been in the 30-40C range and the disk is still its normal temperature.
Posted Aug 10, 2022, 4:35 PM UTC · edited
Good info. Was wondering if/when we'd hear about any helium issues. Seems it's a non-issue though even with a significant decrease in that value. It could possibly be a faulty sensor too?
Afaik there is no dedicated sensor, the drive firmware is monitoring the motor current which indicates the drag of the platters in whichever gas mixture it is spinning in. As helium is dissipating the drag on the platters and thus the current increases.
I figured they'd come up with something clever. Just curious how accurate it is and/or what happens to OP's disk as the helium counter gets to zero.
I found this:
https://forum.hddguru.com/viewtopic.php?f=1&t=35770
And mentioning this:
Method to detect helium leakage from a disk drive (US patent #434987): http://patentimages.storage.googleapis.com/pdfs/US7434987.pdf
Great info! Thanks!
Could this result in a sudden failure rather drive errors slowly mounting?
Like a burnt out or overloaded motor?
Absolutely
Remember, backups are backups. Sync, copy, and RAID are not backups.
Maybe, but not sure I would expect it to intermittently but consistently decrease. But possible that is a failed sensor behavior as well.
Are the other ones still showing 100?
Yes they are. Good question, I will add that.
How have temps been? Maybe you haven't monitored that detail over time, but I'd be curious maybe how it's running compared to the other disks at least? Sorry for so many questions. Just am interested in failure mode if something does happen. If it does fail, it will likely be pretty catastrophic as the helium escapes and head can't maintain it's minimum fly height will likely crash with the disc. But who knows. Thanks for sharing.
I wonder what will happen if the drive is stopped, cooled, and restarted in the absence of helium.
From my understanding and articles I've read is that the flying height of the head is calibrated to helium and loss of helium will result in a head crash in pretty short order. I'm sure a startup would propagate that catastrophe pretty quickly. Although they never said how much helium could be lost before running into issue. Considering OP's hard drive has lot over 80% according to the sensors, it's promising if it keeps running regardless.