Volume Management

Create

curl -v "http://10.196.59.198:17010/admin/createVol?name=test&capacity=100&owner=cfs&mpCount=3"

Create a volume for the user and allocate a set of data shards and metadata shards.By default, when creating a new volume, 10 data shards and 3 metadata shards are allocated.

CubeFS uses the Owner parameter as the user ID.

  • When creating a volume, if there is no user with the same name as the Owner of the volume in the cluster, a user with the ID Owner will be created automatically.
  • If a user with the ID Owner already exists in the cluster, the ownership of the volume will be automatically assigned to that user.

For more information, please refer to: User Guide

Parameter List

ParameterTypeDescriptionRequiredDefault Value
namestringVolume nameYesNone
volTypeintVolume type: 0: replica volume, 1: erasure-coded volumeNo0
capacityintVolume quota, in GBYesNone
ownerstringVolume owner, also the user IDYesNone
mpCountintNumber of initialized metadata shardsNo3
dpCountintNumber of initialized data shardsNodefault 10, maximum limit 200
replicaNumintNumber of replicasNo3 for replica volume (supports 1, 3), 1 for erasure-coded volume (supports 1-16)
dpSizeintMaximum data shard size, in GBNo120
enablePosixAclboolWhether to configure POSIX permission restrictionsNofalse
followerReadboolWhether to allow reading data from followers, true by default for erasure-coded volume. If set to true, the client also needs to configure this field to trueNofalse
crossZoneboolWhether to cross regions. If set to true, the zoneName parameter cannot be setNofalse
normalZonesFirstboolWhether to prioritize writing to normal domainsNofalse
zoneNamestringSpecify the regionNodefault if crossZone is set to false
cacheRuleKeystringUsed for erasure-coded volumeNoOnly data matching this field will be written to the cache if it is not empty
ebsBlkSizeintSize of each block, in bytesNoDefault 8M
cacheCapintSize of the erasure-coded volume cache, in GBNoRequired if the cache is enabled for the erasure-coded volume
cacheActionintThe scenario for writing the erasure-coded volume cache: 0 - do not write to the cache, 1 - read data and write back to the cache, 2 - read and write data to the cacheNo0
cacheThresholdintThe minimum size of data to be written to the cache, in bytesNoDefault 10M
cacheTTLintThe erasure-coded volume cache eviction time, in daysNoDefault 30
cacheHighWaterintThe threshold for erasure-coded volume cache eviction, the upper limit of the content to be evicted, when it reaches this value, the eviction is triggeredNoDefault 80, i.e., when the content of dp reaches 96G (120G * 80/100), the dp starts to evict data
cacheLowWaterintThe lower limit of the capacity to be evicted when it reaches this value, the dp will no longer evict dataNoDefault 60, i.e., when the content of dp reaches 72G (120G * 60/100), the dp will no longer evict data
cacheLRUIntervalintThe detection cycle for low-capacity eviction, in minutesNoDefault 5 minutes

Delete

curl -v "http://10.196.59.198:17010/vol/delete?name=test&authKey=md5(owner)"

First, mark the volume as logically deleted (set status to 1), then delete all data shards and metadata shards through periodic tasks, and finally delete them from persistent storage.

Note

  1. The erasure-coded volume can only be deleted when the usage size is 0.
  2. From v3.3.1 onwards, the volume's Dentry count must be less than the value of the configuration field volDeletionDentryThreshold before deletion is allowed. This configuration field is an integer number and the default value is 0.

When deleting a volume, all permission information related to the volume will be deleted from all user information.

Parameter List

ParameterTypeDescription
namestringVolume name
authKeystringCalculate the 32-bit MD5 value of the owner field of vol as authentication information

Query Volume Details

curl -v "http://10.196.59.198:17010/admin/getVol?name=test" | python -m json.tool

Displays basic information about the volume, including the name of the volume, information about all data shards and metadata shards, etc.

Parameter List

ParameterTypeDescription
namestringVolume name

Response Example

{
    "Authenticate": false,
     "CacheAction": 0,
     "CacheCapacity": 0,
     "CacheHighWater": 80,
     "CacheLowWater": 60,
     "CacheLruInterval": 5,
     "CacheRule": "",
     "CacheThreshold": 10485760,
     "CacheTtl": 30,
     "Capacity": 10,
     "CreateTime": "2022-03-31 16:08:31",
     "CrossZone": false,
     "DefaultPriority": false,
     "DefaultZonePrior": false,
     "DentryCount": 0,
     "Description": "",
     "DomainOn": false,
     "DpCnt": 0,
     "DpReplicaNum": 16,
     "DpSelectorName": "",
     "DpSelectorParm": "",
     "FollowerRead": true,
     "ID": 706,
     "InodeCount": 1,
     "MaxMetaPartitionID": 2319,
     "MpCnt": 3,
     "MpReplicaNum": 3,
     "Name": "abc",
     "NeedToLowerReplica": false,
     "ObjBlockSize": 8388608,
     "Owner": "cfs",
     "PreloadCapacity": 0,
     "RwDpCnt": 0,
     "Status": 0,
     "VolType": 1,
     "ZoneName": "default"
}

Query Volume Data Shard Details

curl -v "http://192.168.0.12:17010/client/partitions?name=ltptest" | python -m json.tool

Displays information about all data shards of the volume.

Parameter List

ParameterTypeDescription
namestringVolume name

Response Example

{
    "Epoch": 0,
    "Hosts": [
        "192.168.0.34:17310",
        "192.168.0.33:17310",
        "192.168.0.32:17310"
    ],
    "IsRecover": false,
    "LeaderAddr": "192.168.0.33:17310",
    "PartitionID": 4,
    "ReplicaNum": 3,
    "Status": 2
}

Query Volume Metadata Shard Details

curl -v "http://192.168.0.12:17010/client/metaPartitions?name=ltptest" | python -m json.tool

Displays information about all metadata shards of the volume.

Parameter List

ParameterTypeDescription
namestringVolume name

Response Example

{
    "DentryCount": 1,
    "End": 16777216,
    "InodeCount": 1,
    "IsRecover": false,
    "LeaderAddr": "192.168.0.23:17210",
    "MaxInodeID": 3,
    "Members": [
        "192.168.0.22:17210",
        "192.168.0.23:17210",
        "192.168.0.24:17210"
    ],
    "PartitionID": 1,
    "Start": 0,
    "Status": 2
}

Statistics

curl -v http://10.196.59.198:17010/client/volStat?name=test

Displays the total space size, used space size, and whether read-write token control is enabled for the volume.

Parameter List

ParameterTypeDescription
namestringVolume name
versionintVolume version, 0: replica volume, 1: erasure-coded volume, default 0 for replica volume, required for accessing erasure-coded volume

Response Example

{
    "CacheTotalSize": 0,
    "CacheUsedRatio": "",
    "CacheUsedSize": 0,
    "EnableToken": false,
    "InodeCount": 1,
    "Name": "abc-test",
    "TotalSize": 10737418240,
    "UsedRatio": "0.00",
    "UsedSize": 0
}

Update

curl -v "http://10.196.59.198:17010/vol/update?name=test&capacity=100&authKey=md5(owner)"

Increases the quota of the volume and adjusts other related parameters.

Parameter List

ParameterTypeDescriptionRequired
namestringVolume nameYes
descriptionstringVolume description informationNo
authKeystringCalculate the 32-bit MD5 value of the owner field of vol as authentication informationYes
capacityintUpdate the datanode capacity of the volume, in GB. The replica volume cannot be less than the used capacityNo
zoneNamestringThe region where the volume is located after the update. If not set, it will be updated to the default regionYes
followerReadboolWhether to allow reading data from followersNo
enablePosixAclboolWhether to configure POSIX permission restrictionsNo
emptyCacheRulestringWhether to empty the cacheRuleNo
cacheRuleKeystringCache rule, used for erasure-coded volume. Only data that meets the corresponding rule will be cachedNo
ebsBlkSizeintThe size of each block of the erasure-coded volumeNo
cacheCapintThe capacity of the cache when the erasure-coded volume uses the secondary cacheNo
cacheActionintFor erasure-coded volume, 0: do not write to the cache, 1: read data and write to the cache, 2: read and write data to the cacheNo
cacheThresholdintThe size limit of the cached file. Only files smaller than this value will be written to the cacheNo
cacheTTLintCache expiration time, in daysNo
cacheHighWaterintEviction high water markNo
cacheLowWaterintCache eviction low water markNo
cacheLRUIntervalintCache detection cycle, in minutesNo

Get Volume List

curl -v "http://10.196.59.198:17010/vol/list?keywords=test"

Gets a list of all volumes, filtered by keyword.

Parameter List

ParameterTypeDescriptionRequired
keywordsstringGet the information of the volume whose name contains this keywordNo

Response Example

[
   {
       "Name": "test1",
       "Owner": "cfs",
       "CreateTime": 0,
       "Status": 0,
       "TotalSize": 155515112832780000,
       "UsedSize": 155515112832780000
   },
   {
       "Name": "test2",
       "Owner": "cfs",
       "CreateTime": 0,
       "Status": 0,
       "TotalSize": 155515112832780000,
       "UsedSize": 155515112832780000
   }
]

Expand

curl -v "http://10.196.59.198:17010/vol/expand?name=test&capacity=100&authKey=md5(owner) "

Expands the specified volume to the specified capacity.

Parameter List

ParameterTypeDescriptionRequired
namestringVolume nameYes
authKeystringCalculate the 32-bit MD5 value of the owner field of vol as authentication informationYes
capacityintThe quota of the volume after expansion, in GBYes

Shrink

curl -v "http://10.196.59.198:17010/vol/shrink?name=test&capacity=100&authKey=md5(owner) "

Reduces the specified volume to the specified capacity.

Parameter List

ParameterTypeDescriptionRequired
namestringVolume nameYes
authKeystringCalculate the 32-bit MD5 value of the owner field of vol as authentication informationYes
capacityintThe quota of the volume after compression, in GBYes

Trash

curl -v "http://127.0.0.1:17010/vol/setTrashInterval?name=test&authKey=trashInterval=7200" 

Enable/Disable trash feature for the specified volume.

Parameter List

ParameterTypeDescriptionRequired
namestringVolume nameYes
authKeystringCalculate the 32-bit MD5 value of the owner field of vol as authentication informationYes
trashIntervalintThe time interval for cleaning expired data in the trash is specified in minutes. A value of 0 indicates that the trash is disabled, while any other positive value indicates that the trash is enabled.Yes

Two Replicas

Main Issues

Two replicas can support modifications and writes normally (using other dps and their ranges).

  1. Supports setting 2 replicas for a 3-replica volume that has been created, and takes effect when creating a new dp, but not for old dps.
  2. If one of the replicas of a two-replica volume crashes and there is no leader, use the raftForceDel parameter to delete the abnormal replica.

Handling of Exceptional Scenarios

For example, there is a dp with two replicas, A and B.

Exceptional Scenarios for Two-Replica Migration

The migration target is C. The process we implement is to add replica C first, then delete the source A, and during the migration process, B crashes.

Solution:

If B crashes and raft is unavailable, delete B first, wait for the migration to complete, delete A, and then add a replica.

Normal Operating Process with One Replica Crashing, such as B

Without a leader, according to the raft rules, B cannot be deleted with two replicas because it needs to be committed first and then applied, but the condition for committing is that the majority is alive.

Solution:

Force delete B.

Warning

Raft supports the new interface del, and the replica does not use the raft log commit directly (back up the dp data first).

curl "http://127.0.0.1:17010/dataReplica/delete?raftForceDel=true&addr=127.0.0.1:17310&id=47128
  • addr is the address of replica B.
  • id is the partition ID (dpid).
  • raftForceDel is used to force delete the raft replica.
  • The DataNode will check the number of replicas (both the volume and dp must have 2 replicas to prevent improper use) and the force field.

Command Line

  1. Creating a Two-Replica Volume
curl -v "http://192.168.0.11:17010/admin/createVol?name=2replica&capacity=100&owner=cfs&mpCount=3&replicaNum=2&followerRead=true"
  1. Reducing a Three-Replica Volume to Two Replicas
  • Existing data is read-only (batch scripts are recommended)
curl -v "http://192.168.0.13:17010/admin/setDpRdOnly?id=**&rdOnly=true
  • Update the number of replicas for the volume. After the update, the 3-replica partition will be asynchronously reduced to 2 replicas.
curl -v "http://192.168.0.13:17010/vol/update?name=ltptest&replicaNum=2&followerRead=true&authKey=0e20229116d5a9a4a9e876806b514a85"
  • Force delete (used when there is no leader, note: make sure that the replica to be deleted is no longer available)
curl "10.86.180.77:17010/dataReplica/delete?raftForceDel=true&addr=10.33.64.33:17310&id=47128"  

Flow Control

Main Issues

  • Considering the storage components that do not differentiate volume, volume flow control is done on the client side.
  • In a distributed scenario, central control of client traffic is required, with the master acting as the center to ensure IOPS and reduce operational pressure by not adding additional flow control servers.
  • The client uses a power function to control traffic growth, which can grow rapidly in scenarios where resources are abundant.
  • Ensure smooth overall volume flow control.
  • The master can balance client traffic and adaptively adjust it based on client requests.

Configuration Items

There are no configuration items, and settings are done through URL commands.

QOS Flow Control Parameters and Interfaces

  • Enable QOS when creating a volume:
curl -v "http://192.168.0.11:17010/admin/createVol?name=volName&capacity=100&owner=cfs&qosEnable=true&flowWKey=10000"

# Enable QOS, set write traffic to 10000MB
  • Get volume traffic information:
curl  "http://192.168.0.11:17010/qos/getStatus?name=ltptest"
  • Get client data:
curl  "http://192.168.0.11:17010/qos/getClientsInfo?name=ltptest"
  • Update server parameters, enable/disable flow control, and adjust read/write traffic values:
curl  "http://192.168.0.11:17010/qos/update?name=ltptest&qosEnable=true&flowWKey=100000"|jq

Fields involved include:

  • FlowWKey = "flowWKey" // Write (volume)
  • FlowRKey = "flowRKey" // Read (volume)

Explanation of Some System Parameters

  1. Default Unit

Currently, whether on the client or datanode side, traffic is measured in MB.

  1. Minimum Traffic and IO Parameters

These are settings that apply to datanodes and volumes. If a value is set, the following requirements must be met, otherwise an error will occur:

  • MinFlowLimit = 100 * util.MB
  • MinIoLimit = 100
  1. If no traffic value is set but flow control is enabled, default values (in bytes) will be used:
    • defaultIopsRLimit uint64 = 1 << 16
    • defaultIopsWLimit uint64 = 1 << 16
    • defaultFlowWLimit uint64 = 1 << 35
    • defaultFlowRLimit uint64 = 1 << 35

Communication Between Client and Master

  1. If the client does not receive flow control from the master for a long time, a warning will be logged.
  2. If communication between the client and master fails, the original flow control will be maintained, and a warning will be logged.
  3. If traffic is 0 for a long time, the client will not actively request flow control and will not report to the master to reduce communication requests. The master will clean up client information that has not been reported for a long time.

Cold Volumes

  1. Level 1 cache reads do not count as traffic.
  2. Cache writes are not included in write traffic control.
  3. Everything else counts as traffic.
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