Very large L2ARC

[remonv76]

I've got a weird problem. My L2ARC size is 1.5TB according to the Reporting

I have installed Freenas 9.10 as an iSCSI storage to my vmware environment. I enabled autotuning. Below is my HW config and autotuning settings.

Dell R710
60GB mem
2x intel SSD DC S3510 240GB (2x 200GB cache)
2x intel SSD DC S3700 100GB (60gb mirror log)
MD1220 DAS - 23x 300GB SAS (3x raidz2 vdevs + 2 spares)

L2ARC tuning:
vfs.zfs.l2arc_headroom 2
vfs.zfs.l2arc_noprefetch 0
vfs.zfs.l2arc_norw 0
vfs.zfs.l2arc_write_boost 40000000
vfs.zfs.l2arc_write_max 10000000

As written above, i created a 200GB partition on both S3510 and added these to the zpool as the L2ARC cache. So how is it possible the reporting shows 1.5TB for the L2ARC?
I noticed the L2ARC grew larger when I moved data to the datastore. So is it possible that a certain setting uses the SAS drives as L2ARC?
I think noprefetch is the problem, but i'm not sure....

 

[joeschmuck]

You know, some else had reported having a similar issue and having some value in Exabytes, something which was not possible in reality. Maybe you could search for that posting, it was within the last week or so. I'm not sure what the solution was, if there was a solution.

 

[remonv76]

I found the thread and bugreport. I will monitor progress on that. It is probably cosmetic, so the Reporting is false.
https://forums.freenas.org/index.php?threads/strange-issue-with-l2arc.50453/

https://bugs.freenas.org/issues/21098

https://bugs.freenas.org/issues/19953

I would like to see what the real L2ARC usage is. I will check if there is some tooling that i can use.