Full disclosure - I have not created an erasure code pool yet!
I have been wanting to do the same thing that you are attempting and
have these links saved. I believe this is what you are looking for.
This link is for decompiling the CRUSH rules and recompiling:
https://docs.ceph.com/docs/luminous/rados/operations/crush-map-edits/
This link is for creating the EC rules for 4+2 with only 3 hosts:
https://ceph.io/planet/erasure-code-on-small-clusters/
I hope that helps!
Chris
On 2019-10-18 2:55 pm, Salsa wrote:
Ok, I'm lost here.
How am I supposed to write a crush rule?
So far I managed to run:
#ceph osd crush rule dump test -o test.txt
So I can edit the rule. Now I have two problems:
1. Whats the functions and operations to use here? Is there
documentation anywhere abuot this?
2. How may I create a crush rule using this file? 'ceph osd crush rule
create ... -i test.txt' does not work.
Am I taking the wrong approach here?
--
Salsa
Sent with ProtonMail Secure Email.
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, October 18, 2019 3:56 PM, Paul Emmerich
<paul.emmerich@xxxxxxxx> wrote:
Default failure domain in Ceph is "host" (see ec profile), i.e., you
need at least k+m hosts (but at least k+m+1 is better for production
setups).
You can change that to OSD, but that's not a good idea for a
production setup for obvious reasons. It's slightly better to write a
crush rule that explicitly picks two disks on 3 different hosts
Paul
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Paul Emmerich
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On Fri, Oct 18, 2019 at 8:45 PM Salsa salsa@xxxxxxxxxxxxxx wrote:
> I have probably misunterstood how to create erasure coded pools so I may be in need of some theory and appreciate if you can point me to documentation that may clarify my doubts.
> I have so far 1 cluster with 3 hosts and 30 OSDs (10 each host).
> I tried to create an erasure code profile like so:
> "
>
> ceph osd erasure-code-profile get ec4x2rs
>
> ==========================================
>
> crush-device-class=
> crush-failure-domain=host
> crush-root=default
> jerasure-per-chunk-alignment=false
> k=4
> m=2
> plugin=jerasure
> technique=reed_sol_van
> w=8
> "
> If I create a pool using this profile or any profile where K+M > hosts , then the pool gets stuck.
> "
>
> ceph -s
>
> ========
>
> cluster:
> id: eb4aea44-0c63-4202-b826-e16ea60ed54d
> health: HEALTH_WARN
> Reduced data availability: 16 pgs inactive, 16 pgs incomplete
> 2 pools have too many placement groups
> too few PGs per OSD (4 < min 30)
> services:
> mon: 3 daemons, quorum ceph01,ceph02,ceph03 (age 11d)
> mgr: ceph01(active, since 74m), standbys: ceph03, ceph02
> osd: 30 osds: 30 up (since 2w), 30 in (since 2w)
> data:
> pools: 11 pools, 32 pgs
> objects: 0 objects, 0 B
> usage: 32 GiB used, 109 TiB / 109 TiB avail
> pgs: 50.000% pgs not active
> 16 active+clean
> 16 creating+incomplete
>
> ceph osd pool ls
>
> =================
>
> test_ec
> test_ec2
> "
> The pool will never leave this "creating+incomplete" state.
> The pools were created like this:
> "
>
> ceph osd pool create test_ec2 16 16 erasure ec4x2rs
>
> ====================================================
>
> ceph osd pool create test_ec 16 16 erasure
>
> ===========================================
>
> "
> The default profile pool is created correctly.
> My profiles are like this:
> "
>
> ceph osd erasure-code-profile get default
>
> ==========================================
>
> k=2
> m=1
> plugin=jerasure
> technique=reed_sol_van
>
> ceph osd erasure-code-profile get ec4x2rs
>
> ==========================================
>
> crush-device-class=
> crush-failure-domain=host
> crush-root=default
> jerasure-per-chunk-alignment=false
> k=4
> m=2
> plugin=jerasure
> technique=reed_sol_van
> w=8
> "
> From what I've read it seems to be possible to create erasure code pools with higher than hosts K+M. Is this not so?
> What am I doing wrong? Do I have to create any special crush map rule?
> --
> Salsa
> Sent with ProtonMail Secure Email.
>
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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