[OmniOS-discuss] ZPOOL bug after upgrade to r151020

[John Barfield]

Greetings,

I just want to report that after a clean istall of r151020 I found a bug whereby importing an older zpool from r151012 and running zpool upgrade causes an SSD cache device size to be reported incorrectly. (only 1 out of 4 devices in this instance)

The cache device size is 93gb and arcstat reported it to be 680gb.

I confirmed by monitoring zpool iostat -v and saw the same size being reported.

We've had a lot of weird io lockups (which is how I found the issue, we didnt notice it until a month after) that brings all of our NFS mounts to a screeching halt and this was the only thing I could find to be out of the ordinary on the system.

CPU average @1% , 20% of ram free, no crazy processes waiting on IO. It was completely invisible. At least from my testing using several dtrace scripts from the net.

I can only assume that the incorrect size reporting caused the zpool to fill the cache drive up beyond its physical capacity during periods of heavy load.

I removed all cache devices and then added them back to the zpool. Then all disks reported correctly again. Format/diskinfo always reported correctly so it was specific to zfs.

We're monitoring the NAS closely to see if the issues occur again.


John Barfield
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