Check the OSD ratios. Is one OSD holding more data compared to the others? This can be seen in the Ceph > OSD page, Used (%).
If one of the OSDs is holding a higher percentage compared to others, you can manually set the reweigh via the command line to a lower value to help force a redistribution.
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Can you please explain how you have your ceph cluster set up? It is unconventional to have all SSDs on one host and all HDDs on another host.
Well, some of the SSD OSDs are quite full, therefore the pool using SSDs (I assume you have device class specific rules), sees almost no free space as the fullest OSD is the limit. One thing I noticed is that the OSDs could have more PGs. That might also make it easier for the balancer to actively redistribute some PGs to use the space of the OSDs better.
Do you have any target_size or target_ratios defined? If not, please do so. This helps the autoscaler to know the estimated size usage of the pools and calculate their PG number accordingly to get to a target of about 100 PGs per OSD. The result should be more PGs, and therefore smaller PGs which help to distribute the stored data more evenly.
Ideally, you will set target_ratios as those are weighted against the other pools (in the same device class). The autoscaler will change the pg_num of a pool automatically if the optimal PG number is off from the current one by a factor of 3 or more. If it is smaller, you have to set it manually to the optimal value.
If you have device specific rules, make sure that each pool is assigned to one and that no pool is using the default "replicated_rule" anymore. It does not make a distinction regarding device class and will confuse the autoscaler.
Do you have any target_size or target_ratios defined? If not, please do so. This helps the autoscaler to know the estimated size usage of the pools and calculate their PG number accordingly to get to a target of about 100 PGs per OSD. The result should be more PGs, and therefore smaller PGs which help to distribute the stored data more evenly.
Ideally, you will set target_ratios as those are weighted against the other pools (in the same device class). The autoscaler will change the pg_num of a pool automatically if the optimal PG number is off from the current one by a factor of 3 or more. If it is smaller, you have to set it manually to the optimal value.
If you have device specific rules, make sure that each pool is assigned to one and that no pool is using the default "replicated_rule" anymore. It does not make a distinction regarding device class and will confuse the autoscaler.
Hmm okay. So if you edit the pool and enable the "Advanced" checkbox next to the OK buttons, do you have a target_ratio set? If not, please do so, a "1" should be plenty fine. The .mgr pool can be ignored as it will not take ip any significant amount of space.
If the pool does not have any target_ratio set, then the autoscaler can only take the currently used space of the pool. I assume that it will recommend double the current number of PGs.
Looking through the list of OSDs more closely, I realize that you only have 2 Nodes that contain HDD OSDs and 5 with SSDs (correct me if I am wrong).
The number of OSDs varies quite a bit between the nodes. This means, that some nodes get quite a bit more traffic as they store more data than others. This can be seen in the "weight" column of the
The idea is, to create two rules, one targeting HDDs, one SSDs and assign each rule to one pool. Then you would have a fast SSD pool and a slow HDD pool and can place the disk images as you need.
Since only two nodes contain HDD OSDs, it doesn't really make sense to create two pools, as you would usually want to have a size/min_size of 3/2. But that means, that you would need at least 3 nodes with OSDs of that device class.
So for now, you will see a mixed bag regarding the performance of the cluster, depending on where the data you want to access is stored.
Regarding the full problem: Please set a target ratio for the pool "ceph-vm" and if the autoscaler then recommends 2048 PGs, set it to that. It won't do it automatically as it is only a change by a factor of 2.
This might help already to redistribute the data more evenly.
Additionally, keep an eye on the balancer. If it is done, you should see it returning this:
If the pool does not have any target_ratio set, then the autoscaler can only take the currently used space of the pool. I assume that it will recommend double the current number of PGs.
Looking through the list of OSDs more closely, I realize that you only have 2 Nodes that contain HDD OSDs and 5 with SSDs (correct me if I am wrong).
The number of OSDs varies quite a bit between the nodes. This means, that some nodes get quite a bit more traffic as they store more data than others. This can be seen in the "weight" column of the
ceph osd df tree output.The idea is, to create two rules, one targeting HDDs, one SSDs and assign each rule to one pool. Then you would have a fast SSD pool and a slow HDD pool and can place the disk images as you need.
Since only two nodes contain HDD OSDs, it doesn't really make sense to create two pools, as you would usually want to have a size/min_size of 3/2. But that means, that you would need at least 3 nodes with OSDs of that device class.
So for now, you will see a mixed bag regarding the performance of the cluster, depending on where the data you want to access is stored.
Regarding the full problem: Please set a target ratio for the pool "ceph-vm" and if the autoscaler then recommends 2048 PGs, set it to that. It won't do it automatically as it is only a change by a factor of 2.
This might help already to redistribute the data more evenly.
Additionally, keep an eye on the balancer. If it is done, you should see it returning this:
Code:
"optimize_result": "Unable to find further optimization, or pool(s) pg_num is decreasing, or distribution is already perfect",Can you post the current output of
Please also provide the output of
Please also post the output of
ceph osd df tree?Please also provide the output of
pveceph pool ls --noborder. Please make sure that the window is wide enough, as the command will just cut off anything that doesn't fit.Please also post the output of
pveversion -v, or if you click on a node -> summary -> Package versions (top left)
From what I can see, osd.6 is the one which is fullest at the moment (~85%), but not as full as yesterday (~87%). I assume that Ceph is currently rebalancing quite some data.
How is the situation in the meantime. Do you see a bit more space, or is it still decreasing?
The whole increasing of the PGs and rebalancing the data can take some time.
Once the cluster has scaled the PGs to 2048 and is done rebalancing, check the usage again and if there are OSDs that are considerably higher than others.
The status of the balancer would be interesting as well, as it should then see where it can improve the data distribution leading to more evenly used OSDs.
How is the situation in the meantime. Do you see a bit more space, or is it still decreasing?
The whole increasing of the PGs and rebalancing the data can take some time.
Once the cluster has scaled the PGs to 2048 and is done rebalancing, check the usage again and if there are OSDs that are considerably higher than others.
The status of the balancer would be interesting as well, as it should then see where it can improve the data distribution leading to more evenly used OSDs.
Okay, that would have been useful information
As long as you have a single OSD that is much fuller than the others, it will be the limiting factor for how much space is estimated as free.
That is why an increase in the PG_num should result in a better distribution and therefore that one full OSD, and other also rather full OSDs, should have more free space. But until then it can take some time.
Out of curiosity, can you post the output of
ceph -s and are there any Global flags enabled? (OSD panel)
Hmm, is the recovery done?
Could you post
Having the disks spread out that unevenly among the cluster nodes might be an issue that could prevent Ceph from balancing the data more evenly. But honestly, there are enough nodes in the cluster that it should work out okayish.
Could you post
ceph -s, ceph osd df tree and ceph balancer status again?Having the disks spread out that unevenly among the cluster nodes might be an issue that could prevent Ceph from balancing the data more evenly. But honestly, there are enough nodes in the cluster that it should work out okayish.
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