Just a general question
marty.godsey
6 Posts
July 15, 2025, 12:54 pmQuote from marty.godsey on July 15, 2025, 12:54 pmHello,
I am learning CEPH and PetaSAN and just want to confirm something to make sure I am understanding this properly.
In this screenshot of a pool configuration, this tells me that out of the three nodes I have, I can loose one and still be operational? Correct?
Thank you for the help.
Hello,
I am learning CEPH and PetaSAN and just want to confirm something to make sure I am understanding this properly.
In this screenshot of a pool configuration, this tells me that out of the three nodes I have, I can loose one and still be operational? Correct?
Thank you for the help.
admin
3,054 Posts
July 15, 2025, 10:40 pmQuote from admin on July 15, 2025, 10:40 pmYes
size 3 means you have 3 copies of all objects, you can lose 2 nodes and still have 1 copy of data, so no loss of data
min size 2 means your pool will remain active, serving i/o if you lose 1 mode.
Yes
size 3 means you have 3 copies of all objects, you can lose 2 nodes and still have 1 copy of data, so no loss of data
min size 2 means your pool will remain active, serving i/o if you lose 1 mode.
marty.godsey
6 Posts
July 16, 2025, 1:30 amQuote from marty.godsey on July 16, 2025, 1:30 amThank you for the answer.
Can it be changed now? If I have three copies, can I change this to 1 on the fly?
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
Thank you for all the help.
Thank you for the answer.
Can it be changed now? If I have three copies, can I change this to 1 on the fly?
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
Thank you for all the help.
marty.godsey
6 Posts
July 24, 2025, 6:26 amQuote from marty.godsey on July 24, 2025, 6:26 ambump.
If I have three copies and I want to change the minimum node from 1 to 2, can this be modified on the fly?
bump.
If I have three copies and I want to change the minimum node from 1 to 2, can this be modified on the fly?
neiltorda
108 Posts
July 24, 2025, 3:58 pmQuote from neiltorda on July 24, 2025, 3:58 pm
Quote from marty.godsey on July 16, 2025, 1:30 am
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
As I understand it, you need to have 2 copies online at any time when running 3/2, but there are 3 copies of the data. So you probably do want to keep nodes in multiples of 3 for best redundancy.
I do think you could switch to 3/1, but not sure why you would.
Quote from marty.godsey on July 16, 2025, 1:30 am
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
As I understand it, you need to have 2 copies online at any time when running 3/2, but there are 3 copies of the data. So you probably do want to keep nodes in multiples of 3 for best redundancy.
I do think you could switch to 3/1, but not sure why you would.
Just a general question
marty.godsey
6 Posts
Quote from marty.godsey on July 15, 2025, 12:54 pmHello,
I am learning CEPH and PetaSAN and just want to confirm something to make sure I am understanding this properly.
In this screenshot of a pool configuration, this tells me that out of the three nodes I have, I can loose one and still be operational? Correct?
Thank you for the help.
Hello,
I am learning CEPH and PetaSAN and just want to confirm something to make sure I am understanding this properly.
In this screenshot of a pool configuration, this tells me that out of the three nodes I have, I can loose one and still be operational? Correct?
Thank you for the help.
admin
3,054 Posts
Quote from admin on July 15, 2025, 10:40 pmYes
size 3 means you have 3 copies of all objects, you can lose 2 nodes and still have 1 copy of data, so no loss of data
min size 2 means your pool will remain active, serving i/o if you lose 1 mode.
Yes
size 3 means you have 3 copies of all objects, you can lose 2 nodes and still have 1 copy of data, so no loss of data
min size 2 means your pool will remain active, serving i/o if you lose 1 mode.
marty.godsey
6 Posts
Quote from marty.godsey on July 16, 2025, 1:30 amThank you for the answer.
Can it be changed now? If I have three copies, can I change this to 1 on the fly?
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
Thank you for all the help.
Thank you for the answer.
Can it be changed now? If I have three copies, can I change this to 1 on the fly?
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
Thank you for all the help.
marty.godsey
6 Posts
Quote from marty.godsey on July 24, 2025, 6:26 ambump.
If I have three copies and I want to change the minimum node from 1 to 2, can this be modified on the fly?
bump.
If I have three copies and I want to change the minimum node from 1 to 2, can this be modified on the fly?
neiltorda
108 Posts
Quote from neiltorda on July 24, 2025, 3:58 pmQuote from marty.godsey on July 16, 2025, 1:30 am
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
As I understand it, you need to have 2 copies online at any time when running 3/2, but there are 3 copies of the data. So you probably do want to keep nodes in multiples of 3 for best redundancy.
I do think you could switch to 3/1, but not sure why you would.
Quote from marty.godsey on July 16, 2025, 1:30 am
I will be adding more nodes to the cluster before I go full production. I was wanting to have 7 nodes, but if I have a multiple of 3, should I only do 6 instead of 7?
As I understand it, you need to have 2 copies online at any time when running 3/2, but there are 3 copies of the data. So you probably do want to keep nodes in multiples of 3 for best redundancy.
I do think you could switch to 3/1, but not sure why you would.