Playing with ZFS on SSDs
No longer used. Consider this totally obsolete.
4 SSDs added:
root@duo:~# ls -la /dev/disk/by-id/
total 0
drwxr-xr-x 2 root root 700 Apr 6 12:01 .
drwxr-xr-x 6 root root 120 Apr 6 12:01 ..
lrwxrwxrwx 1 root root 9 Apr 6 12:01 ata-KINGSTON_SV300S37A120G_50026B773A0059B3 -> ../../sdb
lrwxrwxrwx 1 root root 9 Apr 6 12:01 ata-MKNSSDSR120GB_MB2002101005FEB0D -> ../../sda
lrwxrwxrwx 1 root root 9 Apr 6 11:57 ata-Samsung_SSD_870_EVO_500GB_S62ANZ0R412333F -> ../../sdd
lrwxrwxrwx 1 root root 9 Apr 6 11:57 ata-Samsung_SSD_870_EVO_500GB_S62ANZ0R412361R -> ../../sdc
...
Smaller mirror pool will be btr, and a larger one - bmp.
Create pool btr:
zpool create btr -o ashift=12 mirror \
/dev/disk/by-id/ata-KINGSTON_SV300S37A120G_50026B773A0059B3 \
/dev/disk/by-id/ata-MKNSSDSR120GB_MB2002101005FEB0D
List pools:
root@duo:~# zpool list
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
btr 111G 108K 111G - - 0% 0% 1.00x ONLINE -
Pool status:
root@duo:~# zpool status btr
pool: btr
state: ONLINE
config:
NAME STATE READ WRITE CKSUM
btr ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
ata-KINGSTON_SV300S37A120G_50026B773A0059B3 ONLINE 0 0 0
ata-MKNSSDSR120GB_MB2002101005FEB0D ONLINE 0 0 0
errors: No known data errors
Pool attributes:
root@duo:~# zpool get all btr
NAME PROPERTY VALUE SOURCE
btr size 111G -
btr capacity 0% -
btr altroot - default
btr health ONLINE -
btr guid 7620279620939404162 -
btr version - default
btr bootfs - default
btr delegation on default
btr autoreplace off default
btr cachefile - default
btr failmode wait default
btr listsnapshots off default
btr autoexpand off default
btr dedupratio 1.00x -
btr free 111G -
btr allocated 372K -
btr readonly off -
btr ashift 12 local
btr comment - default
btr expandsize - -
btr freeing 0 -
btr fragmentation 0% -
btr leaked 0 -
btr multihost off default
btr checkpoint - -
btr load_guid 17512845552757542485 -
btr autotrim off default
btr compatibility off default
btr feature@async_destroy enabled local
btr feature@empty_bpobj enabled local
btr feature@lz4_compress active local
btr feature@multi_vdev_crash_dump enabled local
btr feature@spacemap_histogram active local
btr feature@enabled_txg active local
btr feature@hole_birth active local
btr feature@extensible_dataset enabled local
btr feature@embedded_data active local
btr feature@bookmarks enabled local
btr feature@filesystem_limits enabled local
btr feature@large_blocks enabled local
btr feature@large_dnode enabled local
btr feature@sha512 enabled local
btr feature@skein enabled local
btr feature@edonr enabled local
btr feature@userobj_accounting enabled local
btr feature@encryption enabled local
btr feature@project_quota enabled local
btr feature@device_removal enabled local
btr feature@obsolete_counts enabled local
btr feature@zpool_checkpoint enabled local
btr feature@spacemap_v2 active local
btr feature@allocation_classes enabled local
btr feature@resilver_defer enabled local
btr feature@bookmark_v2 enabled local
btr feature@redaction_bookmarks enabled local
btr feature@redacted_datasets enabled local
btr feature@bookmark_written enabled local
btr feature@log_spacemap active local
btr feature@livelist enabled local
btr feature@device_rebuild enabled local
btr feature@zstd_compress enabled local
btr feature@draid enabled local
Note:
- btr feature@lz4_compress active local
Dataset
Create a dataset with the best attribute values:
zfs create -o atime=off -o xattr=sa -o recordsize=64K btr/dset
Note the effect of atime=off present in dataset and not in the pool:
root@duo:~# mount |grep btr
btr on /btr type zfs (rw,xattr,noacl)
btr/dset on /btr/dset type zfs (rw,noatime,xattr,noacl)
Show all the dataset attributes:
root@duo:~# zfs get all btr/dset
NAME PROPERTY VALUE SOURCE
btr/dset type filesystem -
btr/dset creation Thu Apr 6 13:24 2023 -
btr/dset used 3.82G -
btr/dset available 104G -
btr/dset referenced 3.82G -
btr/dset compressratio 1.00x -
btr/dset mounted yes -
btr/dset quota none default
btr/dset reservation none default
btr/dset recordsize 64K local
btr/dset mountpoint /btr/dset default
btr/dset sharenfs off default
btr/dset checksum on default
btr/dset compression lz4 inherited from btr
btr/dset atime off local
btr/dset devices on default
btr/dset exec on default
btr/dset setuid on default
btr/dset readonly off default
btr/dset zoned off default
btr/dset snapdir hidden default
btr/dset aclmode discard default
btr/dset aclinherit restricted default
btr/dset createtxg 16 -
btr/dset canmount on default
btr/dset xattr sa local
btr/dset copies 1 default
btr/dset version 5 -
btr/dset utf8only off -
btr/dset normalization none -
btr/dset casesensitivity sensitive -
btr/dset vscan off default
btr/dset nbmand off default
btr/dset sharesmb off default
btr/dset refquota none default
btr/dset refreservation none default
btr/dset guid 13545457973833480350 -
btr/dset primarycache all default
btr/dset secondarycache all default
btr/dset usedbysnapshots 0B -
btr/dset usedbydataset 3.82G -
btr/dset usedbychildren 0B -
btr/dset usedbyrefreservation 0B -
btr/dset logbias latency default
btr/dset objsetid 87 -
btr/dset dedup off default
btr/dset mlslabel none default
btr/dset sync standard default
btr/dset dnodesize legacy default
btr/dset refcompressratio 1.00x -
btr/dset written 3.82G -
btr/dset logicalused 3.82G -
btr/dset logicalreferenced 3.82G -
btr/dset volmode default default
btr/dset filesystem_limit none default
btr/dset snapshot_limit none default
btr/dset filesystem_count none default
btr/dset snapshot_count none default
btr/dset snapdev hidden default
btr/dset acltype off default
btr/dset context none default
btr/dset fscontext none default
btr/dset defcontext none default
btr/dset rootcontext none default
btr/dset relatime off default
btr/dset redundant_metadata all default
btr/dset overlay on default
btr/dset encryption off default
btr/dset keylocation none default
btr/dset keyformat none default
btr/dset pbkdf2iters 0 default
btr/dset special_small_blocks 0 default
Benchmarking
Test writing:
root@duo:~# dd if=/dev/zero of=/btr/dset/file.out bs=4096 count=1000000 oflag=direct
1000000+0 records in
1000000+0 records out
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 10.8795 s, 376 MB/s
File created:
root@duo:~# ls -la /btr/dset/file.out
-rw-r--r-- 1 root root 4096000000 Apr 6 13:40 /btr/dset/file.out
Test reading:
root@duo:~# dd if=/btr/dset/file.out of=/dev/null bs=4096
1000000+0 records in
1000000+0 records out
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 3.04251 s, 1.3 GB/s