I've just rejiged my NAS by creating 11 vdevs of two disk HDD mirrors, a three-wide SSD mirror special vdev with 2x HDD spares and 1x SSD spare.
I've set both datasets I have to 32KiB for the metadata block size. However, after reloading all the data to the corresponding datasets, I have the following, truncated for brevity:
So I'm either doing something incorrectly here, which is entirely possible/probable, or something else is odd as by simple math, that special vdev should have more than the 38GB it suggests.
That said, my assumption is that the utilization/filling of said special vdev is automatic, and the simple tweak to the config to adjust the block size to utilize it would be all that's required.
I've set both datasets I have to 32KiB for the metadata block size. However, after reloading all the data to the corresponding datasets, I have the following, truncated for brevity:
Code:
truenas[~]# zpool list -v
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
TEH 121T 57.7T 63.2T - - 0% 47% 1.00x ONLINE /mnt
...
special - - - - - - - - -
mirror-13 928G 38.7G 889G - - 3% 4.17% - ONLINE
gptid/66aaf24d-3c49-11ee-bc86-000c297d3363 932G - - - - - - - ONLINE
gptid/66acf448-3c49-11ee-bc86-000c297d3363 932G - - - - - - - ONLINE
gptid/66b04e38-3c49-11ee-bc86-000c297d3363 932G - - - - - - - ONLINE
Code:
truenas[~]# zdb -Lbbbs -U /data/zfs/zpool.cache TEH
...
Block Size Histogram
block psize lsize asize
size Count Size Cum. Count Size Cum. Count Size Cum.
512: 192K 95.8M 95.8M 192K 95.8M 95.8M 0 0 0
1K: 259K 299M 395M 259K 299M 395M 0 0 0
2K: 215K 570M 965M 215K 570M 965M 0 0 0
4K: 2.01M 8.30G 9.24G 259K 1.42G 2.37G 1.34M 5.37G 5.37G
8K: 1.98M 22.0G 31.2G 240K 2.64G 5.01G 2.02M 17.6G 23.0G
16K: 1.17M 25.8G 57.0G 391K 7.86G 12.9G 2.41M 54.6G 77.6G
32K: 2.57M 117G 174G 2.49M 83.8G 96.7G 2.58M 117G 195G
64K: 7.04M 652G 826G 334K 28.5G 125G 7.06M 653G 848G
128K: 150M 19.0T 19.8T 158M 19.8T 19.9T 150M 19.0T 19.8T
256K: 152M 37.9T 57.7T 154M 38.6T 58.5T 152M 37.9T 57.7T
512K: 0 0 57.7T 0 0 58.5T 0 0 57.7T
1M: 0 0 57.7T 0 0 58.5T 0 0 57.7T
2M: 0 0 57.7T 0 0 58.5T 0 0 57.7T
4M: 0 0 57.7T 0 0 58.5T 0 0 57.7T
8M: 0 0 57.7T 0 0 58.5T 0 0 57.7T
16M: 0 0 57.7T 0 0 58.5T 0 0 57.7TThat said, my assumption is that the utilization/filling of said special vdev is automatic, and the simple tweak to the config to adjust the block size to utilize it would be all that's required.
Last edited: