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update lizardfs goal information

master
Efraim Flashner 6 months ago
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352f86d12b
Signed by: efraim GPG Key ID: 41AAE7DCCA3D8351
  1. 41
      HPC/README.org

41
HPC/README.org

@ -375,7 +375,7 @@ sudo scontrol reconfigure
sudo scontrol update NodeName=octopus?? State=RESUME
#+end_src
And then to test that slurm iss working correctly we test it
And then to test that slurm is working correctly we test it
#+begin_src sh
srun --ntasks=5 --nodelist=octopus?? --label /bin/hostname
@ -606,11 +606,48 @@ To change the replication level you need to choose a configuration from
20 fast : $ed(3,1) { SSD SSD SSD SSD }
#+end_src
It is also possible to query the server for all the available goals
#+begin_src sh
lizardfs-admin list-goals octopus01 9421
Goal definitions:
Id Name Definition
1 1_copy 1_copy: $std _
2 2_copy 2_copy: $std {_ _}
...
18 erasure_code_3_1 erasure_code_3_1: $ec(3,1) {_ _ _ _}
19 slow slow: $ec(3,1) {HDD HDD HDD HDD}
20 fast fast: $std {_ _}
21 2ssd 2ssd: $std {SSD SSD}
...
#+end_src
$std {_ _} means two copies on any two chunkservers, $std {SSD SSD} means
two copies on any two SSD backed chunkservers and $ec(3,1) {_ _ _ _}
means it is chunked across 4 chunkservers, where there are 3 data chunks
and one parity disk, needing a minimum of 3 to retrieve the data. Erasure
coding does decrease greatly write times but it is a good way to store
large armounts of data without taking up lots of space. One option is to
copy unchanging data to a lizardfs array at a faster write speed, 2_copy
for example, and then to change the goal afterward to slow.
To change the replication level
: lizardfs setgoal 2 /lizardfs -r
: lizardfs setgoal 2_copies /lizardfs -r
And to see the replication level:
: lizardfs getgoal /lizardfs
/lizardfs: 2_copies
Lizardfs also keeps deleted files, by default for 30 days. If you need to
recover deleted files (or delete them permanently) then the metadata directory
can be mounted with:
#+begin_src sh
mfsmount /path/to/unused/mount -o mfsmeta
#+end_src
For more information see the lizardfs documentation online
https://dev.lizardfs.com/docs/adminguide/advanced_configuration.html#trash-directory
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