Report actual physical (compressed) L2ARC size
Freenas 11.1-U4 displays wrong L2ARC size in zfs report.
The report shows a usage of 196.7GB whereas the system currently only uses 84GB.
Value keeps increasing over time!
Result from command line (zpool list -v):
cache gptid/4646affb-4029-11e8-97ad-989096db91c2.eli 119G 84.0G 35.2G - 0% 70%
#3 Updated by Alexander Motin over 1 year ago
- Status changed from Unscreened to Not Started
- Priority changed from No priority to Nice to have
I don't think it is a real problem. If I see correctly, that graph shows size of uncompressed L2ARC content, which indeed can be bigger then the device size, and continue grow as soon as L2ARC is still not filled completely. Though indeed we could review what stats show what info to make it consistent.
#4 Updated by Alexander Motin over 1 year ago
After another look I am at the same opinion: L2ARC graph shows values of kstat.zfs.misc.arcstats.l2_size sysctl, reporting size of logical (uncompressed) data stored in L2ARC, that does not match ARC size reporting on the same graph physical (potentially compressed) data. Instead of that sysctl for L2ARC we should account and report kstat.zfs.misc.arcstats.l2_asize.
- Needs Doc changed from Yes to No
- File 32793-l2arc-reporting-cli.png 32793-l2arc-reporting-cli.png added
- File 32793-l2arc-reporting-ui.png 32793-l2arc-reporting-ui.png added
- Status changed from Ready for Testing to Passed Testing
- Needs QA changed from Yes to No
Testing with FreeNAS system:
Build FreeNAS-11.2-U2-INTERNAL86 Platform AMD Ryzen 5 1600 Six-Core Processor Memory 65446MB
Tested in legacy UI:
Created pool1 with cache device. Go to reporting and look up ARC Size graph. L2ARC entry reads 0.0 Min 357.2k Avg 1.1M Max 1.0M Last.
Switch to Shell and enter sysctl kstat.zfs.misc.arcstats.l2_asize. This returns a size of 1091584 (1.09 M).