ZFS default compression algo for contemporary FreeBSD versions

[Volodymyr Kostyrko]

05.07.2013 00:07, Xin Li wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> On 7/4/13 1:44 PM, Volodymyr Kostyrko wrote:
>> 04.07.2013 23:36, Xin Li wrote:
>>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256
>>>
>>> On 7/4/13 1:27 PM, Volodymyr Kostyrko wrote:
>>>> 04.07.2013 19:02, Andriy Gapon wrote:
>>>>> on 04/07/2013 18:57 Volodymyr Kostyrko said the following:
>>>>>> Yes. Much better in terms of speed.
>>>>>
>>>>> And compression too.
>>>>
>>>> Can't really say.
>>>>
>>>> When the code first appeared in stable I moved two of my
>>>> machines (desktops) to LZ4 recreating each dataset. To my
>>>> surprise gain at transition from lzjb was fairly minimal and
>>>> sometimes LZ4 even loses to lzjb in compression size. However
>>>> better compression/decompression speed and moreover earlier
>>>> takeoff when data is incompressible clearly makes lz4 a
>>>> winner.
>>>
>>> I'm interested in this -- what's the nature of data on that
>>> dataset (e.g. plain text? binaries? images?)
>>
>> Triple no. Biggest difference in lzjb favor was at zvol with Mac OS
>> X Snow Leo.
>>
>> Maybe it's just because recordsize is too small on zvols? Anyway
>> the difference was like a 1% or 2%. Can't remember but can retest.
>
> Hmm that's weird.  I haven't tried Mac iSCSI volumes but do have tried
> Windows iSCSI volumes, and lz4 was a win.
>
> It may be helpful if you can post your 'zfs get all <zvol name here>'
> output so we can try to reproduce the problem at lab?

Sorry, my virtual machines are all phased out so can't reproduce.

At most I can see this now with this two pools:

arcade at ar1l0u\/home/arcade# zfs get all ar1l0u/vbox_mac_0_cp
NAME                  PROPERTY              VALUE 
SOURCE
ar1l0u/vbox_mac_0_cp  type                  volume                     -
ar1l0u/vbox_mac_0_cp  creation              ср лип 10 11:55 2013  -
ar1l0u/vbox_mac_0_cp  used                  18,2G                      -
ar1l0u/vbox_mac_0_cp  available             13,0G                      -
ar1l0u/vbox_mac_0_cp  referenced            18,2G                      -
ar1l0u/vbox_mac_0_cp  compressratio         1.11x                      -
ar1l0u/vbox_mac_0_cp  reservation           none 
default
ar1l0u/vbox_mac_0_cp  volsize               30G                        local
ar1l0u/vbox_mac_0_cp  volblocksize          8K                         -
ar1l0u/vbox_mac_0_cp  checksum              sha256 
inherited from ar1l0u
ar1l0u/vbox_mac_0_cp  compression           lzjb                       local
ar1l0u/vbox_mac_0_cp  readonly              off 
default
ar1l0u/vbox_mac_0_cp  copies                1 
default
ar1l0u/vbox_mac_0_cp  refreservation        none 
default
ar1l0u/vbox_mac_0_cp  primarycache          metadata                   local
ar1l0u/vbox_mac_0_cp  secondarycache        all 
default
ar1l0u/vbox_mac_0_cp  usedbysnapshots       0                          -
ar1l0u/vbox_mac_0_cp  usedbydataset         18,2G                      -
ar1l0u/vbox_mac_0_cp  usedbychildren        0                          -
ar1l0u/vbox_mac_0_cp  usedbyrefreservation  0                          -
ar1l0u/vbox_mac_0_cp  logbias               throughput                 local
ar1l0u/vbox_mac_0_cp  dedup                 off 
default
ar1l0u/vbox_mac_0_cp  mlslabel                                         -
ar1l0u/vbox_mac_0_cp  sync                  standard 
default
ar1l0u/vbox_mac_0_cp  refcompressratio      1.11x                      -
ar1l0u/vbox_mac_0_cp  written               18,2G                      -
ar1l0u/vbox_mac_0_cp  logicalused           20,2G                      -
ar1l0u/vbox_mac_0_cp  logicalreferenced     20,2G                      -

arcade at ar1l0u\/home/arcade# zfs get all ar1l0u/vbox_mac_1
NAME               PROPERTY              VALUE                      SOURCE
ar1l0u/vbox_mac_1  type                  volume                     -
ar1l0u/vbox_mac_1  creation              ср чер 26 18:02 2013  -
ar1l0u/vbox_mac_1  used                  5,48G                      -
ar1l0u/vbox_mac_1  available             13,0G                      -
ar1l0u/vbox_mac_1  referenced            18,0G                      -
ar1l0u/vbox_mac_1  compressratio         1.09x                      -
ar1l0u/vbox_mac_1  origin                ar1l0u/vbox_mac_0 at xcode    -
ar1l0u/vbox_mac_1  reservation           none                       default
ar1l0u/vbox_mac_1  volsize               30G                        local
ar1l0u/vbox_mac_1  volblocksize          8K                         -
ar1l0u/vbox_mac_1  checksum              sha256 
inherited from ar1l0u
ar1l0u/vbox_mac_1  compression           lz4 
inherited from ar1l0u
ar1l0u/vbox_mac_1  readonly              off                        default
ar1l0u/vbox_mac_1  copies                1                          default
ar1l0u/vbox_mac_1  refreservation        none                       default
ar1l0u/vbox_mac_1  primarycache          metadata                   local
ar1l0u/vbox_mac_1  secondarycache        all                        default
ar1l0u/vbox_mac_1  usedbysnapshots       0                          -
ar1l0u/vbox_mac_1  usedbydataset         5,48G                      -
ar1l0u/vbox_mac_1  usedbychildren        0                          -
ar1l0u/vbox_mac_1  usedbyrefreservation  0                          -
ar1l0u/vbox_mac_1  logbias               throughput                 local
ar1l0u/vbox_mac_1  dedup                 off                        default
ar1l0u/vbox_mac_1  mlslabel                                         -
ar1l0u/vbox_mac_1  sync                  standard                   default
ar1l0u/vbox_mac_1  refcompressratio      1.13x                      -
ar1l0u/vbox_mac_1  written               5,48G                      -
ar1l0u/vbox_mac_1  logicalused           5,98G                      -
ar1l0u/vbox_mac_1  logicalreferenced     20,2G                      -

The latter is actually a clone of some other pool so I'm not sure 
whether this a result of working with snapshots or a real compression 
difference.

-- 
Sphinx of black quartz, judge my vow.