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Each 12 drive array would have an interesting physical block layout. What was your ASHIFT and what was your physical disk raw sector size because if you had a
by myrond 6y ago
Each 12 drive array would have an interesting physical block layout.
What was your ASHIFT and what was your physical disk raw sector size because if you had a ASHIFT=9 you would have 5120k blocks, if it was a ASHIFT=12 you would have physical 40960 blocks. None of those line up well with zfs.
Additionally if this was a long time ago the pool would have defaulted to ASHIFT=9 and if you added any 4K drives you could have been having write amplification occurring.
Looks as if you had your drives doing a lot of unnecessary extra wasted work.
- aidenn0 6y agoAshift=9 native 512b sector drives
- fomine3 6y agoThis is huge thing (called "Slop Space") that I noticed after I bought all ZFS NAS parts! It wastes much capacity by default if drive count is not ideal. IIRC use larger recordsize (1MB or above) and enable compression almost solves issue. I use default 128K recordsize for small files zvol for performance, and use larger recordsize for the rest of zvols. https://wintelguy.com/zfs-calc.pl https://wintelguy.com/zfs-calc.pl