Presentation slides for running MySQL (InnoDB) on ZFS. Since most databases have analogues to optimisation targets mentioned, it is more broadly applicable.

1. InnoDB on ZFS
ZFS (you’ll wonder how you ever managed
without it)

2. Disk Geometry
● ZFS:
− pools
● mirror vdevs (equivalent of RAID1 / RAID10)
● ashift to match the drives (it may be dangerous to
assume long-term availability of disks with < 4KB sectors)
● versions > v28 aren't cross-compatible, but OpenZFS
v5000 is required for LZ4 compression (LZJB still helps
on v28)

3. Kernel Module Options
● ZFS
− Kernel module
● zfs_prefetch_disable=1

4. File System Options
● ZFS
− File systems
● atime=off
● compression=lz4
● logbias=throughput
● primarycache=metadata
● recordsize=16k (128k for logs)
● xattr=sa

5. MySQL Options
● MySQL
− innodb_flush_method=fsync (O_DIRECT is in ZoL
0.8, but ZFS primarycache=metadata ensures no
double caching)
− innodb_doublewrite=0 (ZFS is copy-on-write and
transactional, precluding partial writes)
− innodb_checksum_algorithm=none (>= 5.6.3)
− innodb_checksum=0 (< 5.6.3)
− Don't use compression – leaving it to ZFS results in
faster performance, lower space consumption and
doesn't break storage alignment

6. Other benefits
● Transparent error detection and self-healing
● Improved performance (compression and CoW)
● Efficient backups in impractical situations
− Snapshots without a performance penalty
− Efficient incremental snapshot transfers
− Efficient Galera state transfers (custom script)

7. Performance (from 2014)
Measured using AWS EBS
MD 4-disk RAID10 + ext4:
SELECT: 169m
INSERT: 140m
UPDATE: 70m
DELETE: 332m
TOTAL: 712m
ZFS 4-disk stripe-of-mirrors
SELECT: 164m (97%)
INSERT: 119m (85%)
UPDATE: 73m (104%)
DELETE: 202m (60%)
TOTAL: 558m (78%)