Enable TRIM for SSDs

[probonopd]

https://www.crucial.com/articles/about-ssd/what-is-trim

Automatically:

Currently it is off

FreeBSD% zpool get autotrim
NAME   PROPERTY  VALUE     SOURCE
zroot  autotrim  off       default

zpool set autotrim=on zroot works, and it also works after rebooting

Manually:

zpool trim <zpool>

Source: https://forums.freebsd.org/threads/how-to-enable-autotrim-for-zfs.86091/

[probonopd]

Does this have any ill effect on non-SSDs?

Can we detect programmatically whether the pool is on a SSD?

[wesbluemarine]

Does this have any ill effect on non-SSDs?

Can we detect programmatically whether the pool is on a SSD?

hello% sudo smartctl -a /dev/ada0 | grep Solid

Rotation Rate:    Solid State Device

[probonopd]

NVME or USB SSDs don't show up under /dev/ada0

[probonopd]

Is there any reason why this is not enabled by default in FreeBSD?

[probonopd]

https://fosstodon.org/@pulkomandy@mastodon.tetaneutral.net/109406855529592690:

The reason it's off by default is more likely that some disks can crash their firmware when receiving commands they don't implement correctly

[grahamperrin]

zpool-trim.8 — OpenZFS documentation

… Can we detect programmatically whether the pool is on a SSD?

zpoolprops.7 — OpenZFS documentation, see autotrim.

[grahamperrin]

Does this have any ill effect on non-SSDs?

Attention to a mobile hard disk drive, and a USB flash drive with a sole partition that's used for L2ARC:

root@mowa219-gjp4-8570p-freebsd:~ # zpool list -v
NAME                    SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
Transcend               464G   334G   130G        -         -    42%    72%  1.00x    ONLINE  -
  gpt/Transcend         466G   334G   130G        -         -    42%  72.0%      -    ONLINE
  indirect-1               -      -      -        -         -      -      -      -    ONLINE
cache                      -      -      -        -         -      -      -      -         -
  gpt/cache-transcend  14.5G  6.44G  8.01G        -         -     0%  44.6%      -    ONLINE
august                  912G   705G   207G        -         -    59%    77%  1.00x    ONLINE  -
  ada0p3.eli            915G   705G   207G        -         -    59%  77.3%      -    ONLINE
cache                      -      -      -        -         -      -      -      -         -
  gpt/cache-august     28.8G  11.9G  16.9G        -         -     0%  41.4%      -    ONLINE
  gpt/cache2-august    14.4G  13.7G   772M        -         -     0%  94.8%      -    ONLINE
root@mowa219-gjp4-8570p-freebsd:~ # lsblk
DEVICE         MAJ:MIN SIZE TYPE                                          LABEL MOUNT
ada0             0:119 932G GPT                                               - -
  ada0p1         0:121 260M efi                                    gpt/efiboot0 -
  <FREE>         -:-   1.0M -                                                 - -
  ada0p2         0:123  16G freebsd-swap                              gpt/swap0 SWAP
  ada0p2.eli     2:50   16G freebsd-swap                                      - SWAP
  ada0p3         0:125 915G freebsd-zfs                                gpt/zfs0 <ZFS>
  ada0p3.eli     0:131 915G zfs                                               - -
  <FREE>         -:-   708K -                                                 - -
da0              0:168 466G GPT                                               - -
  <FREE>         -:-   1.0M -                                                 - -
  da0p1          0:169 466G freebsd-zfs                           gpt/Transcend <ZFS>
da1              0:176  29G GPT                                               - -
  <FREE>         -:-   1.0M -                                                 - -
  da1p1          0:177  29G freebsd-zfs                        gpt/cache-august <ZFS>
da2              0:184  14G GPT                                               - -
  <FREE>         -:-   1.0M -                                                 - -
  da2p1          0:187  14G freebsd-zfs                       gpt/cache2-august <ZFS>
  <FREE>         -:-   1.0M -                                                 - -
da3              0:198  14G GPT                                               - -
  <FREE>         -:-   1.0M -                                                 - -
  da3p1          0:199  14G freebsd-zfs                     gpt/cache-transcend <ZFS>
root@mowa219-gjp4-8570p-freebsd:~ # geom disk list da0 da3
Geom name: da0
Providers:
1. Name: da0
   Mediasize: 500107862016 (466G)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r1w1e3
   descr: StoreJet Transcend
   lunid: 5000000000000001
   ident: X3E1SAKRS
   rotationrate: unknown
   fwsectors: 63
   fwheads: 255

Geom name: da3
Providers:
1. Name: da3
   Mediasize: 15518924800 (14G)
   Sectorsize: 512
   Mode: r1w1e3
   descr: Kingston DataTraveler 3.0
   lunname: KingstonDataTraveler 3.0
   lunid: KingstonDataTraveler 3.0
   ident: 60A44C3FACC93110B9970045
   rotationrate: 0
   fwsectors: 63
   fwheads: 255

root@mowa219-gjp4-8570p-freebsd:~ # zpool trim Transcend
cannot trim: no devices in pool support trim operations
root@mowa219-gjp4-8570p-freebsd:~ # zpool offline Transcend gpt/cache-transcend
root@mowa219-gjp4-8570p-freebsd:~ # zpool trim Transcend gpt/cache-transcend
cannot trim 'gpt/cache-transcend': device is in use as a cache
root@mowa219-gjp4-8570p-freebsd:~ # zpool online Transcend gpt/cache-transcend
root@mowa219-gjp4-8570p-freebsd:~ # sysctl vfs.zfs.l2arc.trim_ahead
vfs.zfs.l2arc.trim_ahead: 0
root@mowa219-gjp4-8570p-freebsd:~ # 

Postscript

Cross-reference:

• zpool-trim(8): cannot trim '⋯': device is in use as a cache · Discussion #14231 · openzfs/zfs

[grahamperrin]

NVME or USB SSDs don't show up under /dev/ada0

That is expected.

ada(4)

da(4)

nvme(4)

So, for example:

% ls /dev/ada*
/dev/ada0       /dev/ada0p1     /dev/ada0p2     /dev/ada0p2.eli /dev/ada0p3     /dev/ada0p3.eli
% ls /dev/da*
/dev/da0        /dev/da1        /dev/da2        /dev/da3
/dev/da0p1      /dev/da1p1      /dev/da2p1      /dev/da3p1
% ls /dev/n*
/dev/netdump    /dev/netmap     /dev/null
% ls /dev/nvme*
ls: No match.
% 

[grahamperrin]

UFS

See tunefs(8) flag -t.

[grahamperrin]

trim

You might be curious about the trim binary,

/usr/sbin/trim

Beware: it's not what some people might expect. From the DESCRIPTION of trim(8):

The trim utility erases (a) specified region of the device. …

So, for example, a dry run:

root@mowa219-gjp4-8570p-freebsd:~ # trim -N da4
trim da4 offset 0 length 2004877312
dry run: add -f to actually perform the operation
root@mowa219-gjp4-8570p-freebsd:~ # 

A non-dry run would erase the device.

root@mowa219-gjp4-8570p-freebsd:~ # geom disk list da4
Geom name: da4
Providers:
1. Name: da4
   Mediasize: 2004877312 (1.9G)
   Sectorsize: 512
   Mode: r1w1e2
   descr: JetFlash Transcend 2GB
   ident: FTRR0IBTVZ58PPPJ
   rotationrate: unknown
   fwsectors: 63
   fwheads: 255
root@mowa219-gjp4-8570p-freebsd:~ # 

[probonopd]

Thanks @grahamperrin. Can you imagine a simple, straightforward shell script that enables TRIM on disks on which it is safe to be enabled?

[grahamperrin]

Not me, sorry, I'm not a scripter.