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Creating a new class apart from ssd in a crush rule.


pradeep suresh
32 Posts
November 22, 2023, 4:52 am

Team,
I am unable to create a new crush rule with a different class in the Petasan, usually I get an error as general crush error.
For the below syntax I get an error, I am trying to create a crush rule for a different size/performance disk.

But on a different cluster with similar class I was able to create this crush rule.

What is the prerequsites for creating a crush rule apart from SSD

{
id 2
type replicated
step take default class ssd8tb
step chooseleaf firstn 0 type host
step emit
}
Log says
 21/11/2023 03:50:57 ERROR Crush Compile Error
 21/11/2023 06:25:05 INFO GlusterFS mount attempt
 21/11/2023 23:10:16 ERROR Crush Compile Error
BELOW are the info related to the OSD and disk in the cluster.
root@uat-ps-node1:~# ceph device ls
DEVICE HOST:DEV DAEMONS WEAR LIFE EXPECTANCY
LOGICAL_VOLUME_600508b1001c0c7edbeeb5f535967144 uat-ps-node3:sdc osd.5
LOGICAL_VOLUME_600508b1001c1d3b1819fbc793063c49 uat-ps-node1:sde osd.9
LOGICAL_VOLUME_600508b1001c25fef696cd7215bc5172 uat-ps-node1:sdb mon.uat-ps-node1
LOGICAL_VOLUME_600508b1001c264f1bb48c7b8f3dc185 uat-ps-node1:sdf osd.11
LOGICAL_VOLUME_600508b1001c36abadccbae03b63fdbd uat-ps-node2:sda osd.8
LOGICAL_VOLUME_600508b1001c3e38d8d93ac85d1c047a uat-ps-node3:sda mon.uat-ps-node3
LOGICAL_VOLUME_600508b1001c47c5ec57c047d3602779 uat-ps-node2:sdd osd.2
LOGICAL_VOLUME_600508b1001c5b1b21ba0be6d33f401a uat-ps-node1:sda osd.0
LOGICAL_VOLUME_600508b1001c5d1f27331643e1efafaf uat-ps-node1:sdd osd.6
LOGICAL_VOLUME_600508b1001c749fcec3f7b95332c26f uat-ps-node1:sdc osd.1
LOGICAL_VOLUME_600508b1001c7b46e603e68fa8d297c2 uat-ps-node3:sdd osd.7
LOGICAL_VOLUME_600508b1001c816537db88b9e56e88d9 uat-ps-node3:sde osd.4
LOGICAL_VOLUME_600508b1001c97f1345b840418dc37c2 uat-ps-node2:sdf osd.12
LOGICAL_VOLUME_600508b1001cafadbbdf3c07d6b9661e uat-ps-node2:sdc osd.3
LOGICAL_VOLUME_600508b1001cc150d9dc34be87608979 uat-ps-node3:sdg osd.13
LOGICAL_VOLUME_600508b1001cc72d384454fc9531c061 uat-ps-node3:sdf osd.10
LOGICAL_VOLUME_600508b1001ce39ac808a56a6f8d8955 uat-ps-node2:sdb mon.uat-ps-node2

ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 38.79520 root default
-3 11.54172 host uat-ps-node1
0 hdd 2.18320 osd.0 up 1.00000 1.00000
1 hdd 2.18320 osd.1 up 1.00000 1.00000
6 ssd 1.86298 osd.6 up 1.00000 1.00000
9 ssd 1.81926 osd.9 up 1.00000 1.00000
11 ssd 3.49309 osd.11 up 1.00000 1.00000
-5 13.17195 host uat-ps-node2
2 hdd 2.18320 osd.2 up 1.00000 1.00000
3 hdd 2.18320 osd.3 up 1.00000 1.00000
8 ssd 1.81926 osd.8 up 1.00000 1.00000
12 ssd 6.98630 osd.12 up 1.00000 1.00000
-7 14.08153 host uat-ps-node3
4 hdd 2.18320 osd.4 up 1.00000 1.00000
5 hdd 2.18320 osd.5 up 1.00000 1.00000
7 ssd 0.90958 osd.7 up 1.00000 1.00000
10 ssd 1.81926 osd.10 up 1.00000 1.00000
13 ssd 6.98630 osd.13 up 1.00000 1.00000

 

root@uat-ps-node1:~# ceph osd crush class ls
[
"hdd",
"ssd"
]
root@uat-ps-node1:~#

#1

admin
2,930 Posts
November 22, 2023, 10:43 am

You need to assign your custom class ss8tb to you osds

#2

pradeep suresh
32 Posts
November 22, 2023, 10:56 am

Thanks for the response.

Firstly problem is that the below CRUSH rule syntax is not working with different class name.
The same class somehow worked on a different cluster. I was able to add the OSD's to a different class ssd8tb in that custer.

{
id 2
type replicated
step take default class ssd8tb
step chooseleaf firstn 0 type host
step emit
}

 

If I am able to create a new class, I can migrate the OSD from SSD class to ssd8tb class.

Ryt now i have only two classes available in the cluster,
SSD
HDD

I get an error if the class is different from above two (SSD HDD).
That is where i need help with.
#3

admin
2,930 Posts
November 22, 2023, 1:12 pm

have you tried my previous reply ? if it did not work, what commands you used and what error you got ?

#4

pradeep suresh
32 Posts
November 22, 2023, 1:20 pm

My Bad,

Worked

Much Thanks

#5