HDDS-4594. Add namespace quota to documentation

[amaliujia]

What changes were proposed in this pull request?

Add namespace quota to documentation

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-4594

How was this patch tested?

UT

[amaliujia]

R: @captainzmc

[captainzmc]

Whether 'e' in Storage Space applies equally to Namespace quota. If so, we need to list.

[captainzmc]

@amaliujia Thanks for your patch. Could you also update the Client Usage about Namespace quota?

[amaliujia]

@captainzmc

comments addressed.

[linyiqun]

When reading this quota documentation, I am thinking for the set quota cases: as we support both volume and bucket quota, will we check the below scenarios that only either one quota was set, then try to enable another quota:

• Bucket quota already set, then user try to set volume quota, will we check volume quota must more than total bucket quota?
• Volume quota already set, then user try to set bucket quota, will we check the total bucket quota, so that will not exceed volume quota? (I remember this check already contained)

[amaliujia]

@linyiqun

I think for namespace, it will be different than space. Namespace quota is independent on each level (volume, bucket, etc.)

Namespace quota on volume only controls number of bucket names, and namespace on bucket only controls keys in that bucket. This is different from space quota in which volume quota has a relationship with its buckets quotas.

What currently is missing is the ability to control all keys within a volume. If there is use case, we could add support for it.

[captainzmc]

Thanks for @amaliujia's update. I think there are some case we need to confirm.
Whether 'f' in Storage Space applies equally to Namespace quota? If so, we need to list. This part of namespace has been modified in #1723 (reviewing).

[captainzmc]

There's something wrong with the directory structure. At present is:
#space quota
……
#namespace quota
……
## clear quota
## check quota and usage

We can change it to:

#space quota
……
## clear quota
## check quota and usage

#namespace quota
……
## clear quota
## check quota and usage

or

#space quota and namespace quota

……
## clear quota
## check quota and usage

[amaliujia]

@captainzmc
f. does not apply to namespace in my opinion. Note that the difference so far for namespace quota is that it is set independently on volume and bucket (not like space quota).

[captainzmc]

@captainzmc
f. does not apply to namespace in my opinion. Note that the difference so far for namespace quota is that it is set independently on volume and bucket (not like space quota).

Agree, I'll remove the namespace restriction in #1723.

[amaliujia]

@captainzmc

finally I was able to re-trigger the CI (seemed that CI didn't work for a while). Any other comments on this PR?

[captainzmc]

LGTM +1
hi @linyiqun, any other suggestions about this PR?

[linyiqun]

Also +1 from me.

[captainzmc]

Merged this PR. Thanks for @amaliujia's patch and @linyiqun‘s review.