### COS Migration

Last updated: 2021-11-25 14:27:02

## Overview

COS Migration is an all-in-one tool that integrates the COS data migration feature. Users can quickly migrate data from various sources to COS through simple configurations and steps. It has the following features:

• Diverse data sources:
• Local data: migrate locally stored data to COS.
• Other cloud storage services: Currently, it supports migration from AWS S3, Alibaba Cloud OSS, and Qiniu to COS. More services will be supported in the future.
• URL list: download and migrate data from specified URLs to COS.
• Bucket replication: data can be replicated among COS buckets. Cross-account and cross-region replication is supported.
• Checkpoint restart: restarting uploads from checkpoints is supported. For large files, if the upload exits halfway or service failure occurs, you can run the tool again to restart the upload.
• Multipart upload: an object can be uploaded to COS by parts.
• Parallel upload: multiple objects can be uploaded at the same time.
• Migration verification: migrated objects can be verified.
Note：

• COS Migration only supports UTF-8 encoding.
• If you use this tool to upload a file whose name already exists, the existing file will be overwritten. You need to configure the tool to skip files with the same name.

## Operating Environments

#### Operating system

Windows, Linux, and macOS.

#### Software dependency

• JDK 1.8 X64 or above. For more information, see Java Installation and Configuration.
• IFUNC needs to be supported on Linux and the binutils version should be later than 2.20.

## Directions

### 2. Decompress the package

#### Windows

Decompress the package and save it to a directory, for example:

C:\Users\Administrator\Downloads\cos_migrate


#### Linux

Decompress the package and save it to a directory, for example:

unzip cos_migrate_tool_v5-master.zip && cd cos_migrate_tool_v5-master


#### Migration tool structure

The structure of the properly decompressed COS Migration tool is as follows:

COS_Migrate_tool
|——conf  #Directory of the configuration file
|   |——config.ini  #Migrate the configuration file
|——db    #Store the record of successful migrations
|——dep   #JAR package complied by the main logic of the program
|——log   #Log generated during tool execution
|——opbin #Script for compiling
|——src   #Source code of the tool
|——tmp   #Temporary file storage directory
|——pom.xml #Project configuration file
|——start_migrate.sh  #Migration startup script for Linux
|——start_migrate.bat #Migration startup script for Windows

Note：

• The db directory mainly records the IDs of files successfully migrated by the tool. Each migration job will first compare the records in the db directory. If the ID of the current file has already been recorded, the current file will be skipped, otherwise it will be migrated.
• The log directory keeps all the logs generated during tool migration. If an error occurs during migration, first check error.log in this directory.

### 3. Modify the config.ini file

Before running the migration startup script, modify the config.ini file (path: ./conf/config.ini) first. This file contains the following parts:

#### 3.1 Configure the migration type

type indicates the migration type, which is filled in by users based on their migration needs. For example, to migrate local data to COS, users need to configure type=migrateLocal for [migrateType].

[migrateType]
type=migrateLocal


Currently, the following migration types are supported:

Migration Type Description
migrateLocal From local system to COS
migrateAws From AWS S3 to COS
migrateAli From Alibaba Cloud OSS to COS
migrateQiniu From Qiniu to COS
migrateBucketCopy From source bucket to destination bucket
migrateUpyun From UpYun to COS

#### 3.2 Configure the migration job

You can configure a migration job based on your actual needs, including information configuration for the destination COS and job-related configurations.

# The common configuration section of the migration tool includes account information to be migrated to the destination COS.
[common]
secretId=COS_SECRETID
secretKey=COS_SECRETKEY
bucketName=examplebucket-1250000000
region=ap-guangzhou
storageClass=Standard
cosPath=/
https=off
tmpFolder=./tmp
smallFileThreshold=5242880
smallFileExecutorNum=64
bigFileExecutorNum=8
entireFileMd5Attached=on
daemonMode=off
daemonModeInterVal=60
executeTimeWindow=00:00,24:00
outputFinishedFileFolder=./result
resume=false
skipSamePath=false

Name Description Default Value
secretId SecretId of your key. Replace COS_SECRETID with your real key information, which can be obtained on the TencentCloud API key page in the CAM Console -
secretKey SecretKey of your key. Replace COS_SECRETKEY with your real key information, which can be obtained on the TencentCloud API key page in the CAM Console -
bucketName Name of the destination bucket in the format of <bucketname-appid>. The bucket name must include the APPID such as examplebucket-1250000000 -
region Region information of the destination bucket. For the region abbreviations in COS, see Regions and Access Domain Names -
storageClass Storage class for the migrated data. Valid values: Standard, Standard_IA, Archive. For more information, please see Storage Class Overview. Standard
cosPath COS path to migrate to. / indicates to migrate to the root path of the bucket, /folder/doc/ indicates to migrate to /folder/doc/ in the bucket. If /folder/doc/ does not exist, a path will be created automatically /
https Whether to transfer via HTTPS. on: Yes, off: No. It takes time to enable transfer via HTTPS, which is suitable for scenarios that demand high security. off
tmpFolder The directory used to store temporary files when data is migrated from another cloud storage service to COS, which will be deleted after the migration is completed. The format must be an absolute path:
The separator on Linux is /, such as /a/b/c
The separator on Windows is \, such as E:\\a\\b\\c
The default value is the tmp directory in the path of the tool
./tmp
smallFileThreshold Number of bytes as the threshold for small files. If the size is greater than or equal to this threshold, multipart upload is used; otherwise, simple upload is used. The default value is 5 MB 5242880
smallFileExecutorNum Concurrency for uploading small files (smaller than smallFileThreshold) via simple upload. Decrease the concurrency if files are uploaded to COS via public network with low bandwidth 64
bigFileExecutorNum Concurrency for uploading large files (greater than or equal to smallFileThreshold) via multipart upload. Decrease the concurrency if files are uploaded to COS via public network with low bandwidth 8
entireFileMd5Attached The migration tool calculates the MD5 of the entire file and stores it in the custom header "x-cos-meta-md5" of the file for subsequent verification, because the ETag of a large file uploaded to COS via multipart upload is not the MD5 of the entire file on
daemonMode Whether to enable daemon mode. on: yes; off: no. In daemon mode, the program will keep performing synchronization. The synchronization interval is configured by the daemonModeInterVal parameter off
daemonModeInterVal Time interval in seconds between two rounds of synchronization 60
executeTimeWindow Execution time window with a granularity in minute, which defines the time period when the migration tool runs jobs. For example:
03:30, 21:00 means that jobs will be run between 03:30 and 21:00, and the tool is in sleep mode at other times, when the migration will be paused and the progress will be retained until the next time window when the migration will resume automatically
00:00,24:00
outputFinishedFileFolder This directory stores the results of successful migration tasks, and result files are named by date, for example, ./result/2021-05-27.out, where ./result is the directory that is created. Each line in the result files is in the format of "Absolute path"\t"File size"\t"Last modified time". If outputFinishedFileFolder is left empty, no results will be output. ./result
resume Whether to continue with the result of the last run and traverse through the list of files from the source. The tool starts from scratch by default. false
skipSamePath Whether to skip the current file if a file with the same name already exists in COS. By default, the tool does not skip the current file: it overwrites the existing file. false

#### 3.3 Configure the data source

Configure each section according to the migration type described in [migrateType]. For example, if the configuration item of [migrateType] is type=migrateLocal, users only need to configure the [migrateLocal] section.

3.3.1 Configure a local data source migrateLocal

If you migrate from a local system to COS, configure this section. The specific configuration items and descriptions are as follows:

# Configuration section for migration from a local system to COS
[migrateLocal]
localPath=E:\\code\\java\\workspace\\cos_migrate_tool\\test_data
excludes=
ignoreModifiedTimeLessThanSeconds=

Configuration Item Description
localPath Absolute path of the local directory
• Linux uses a slash (/) as the delimiter, for example, /a/b/c
• Windows uses two backlashes (\) as the delimiter, for example, E:\\a\\b\\c
excludes Absolute path of the directory or file to be excluded, meaning some directories or files under localPath are not to be migrated. Multiple absolute paths are separated by semicolons. If this is left blank, all files in localPath will be migrated
ignoreModifiedTimeLessThanSeconds Exclude files whose update time is less than a certain period of time from the current time. Unit in seconds. This is left blank by default, indicating files are not to be filtered by the time specified by lastmodified. This is suitable for scenarios where users run the migration tool while updating files, and do not want files being updated to be migrated to COS. For example, if this is configured as 300, only files updated at least 5 minutes ago will be uploaded

3.3.2 Configure an Alibaba Cloud OSS data source migrateAli

If you migrate from Alibaba Cloud OSS to COS, configure this section. The specific configuration items and descriptions are as follows:

# Configuration section for migration from Alibaba Cloud OSS to COS
[migrateAli]
bucket=bucket-aliyun
accessKeyId=yourAccessKeyId
accessKeySecret=yourAccessKeySecret
endPoint= oss-cn-hangzhou.aliyuncs.com
prefix=
proxyHost=
proxyPort=

Configuration Item Description
bucket Name of the Alibaba Cloud OSS bucket
accessKeyId Replace yourAccessKeyId with your SecretId
accessKeySecret Replace yourAccessKeySecret with your SecretKey
endPoint Address of the Alibaba Cloud endpoint
prefix Prefix of the path to be migrated. If all data in the bucket needs to be migrated, leave the prefix blank
proxyHost If you want to use a proxy for access, enter the proxy IP address
proxyPort Proxy port

3.3.3 Configure an AWS data source migrateAws

If you migrate from AWS to COS, configure this section. The specific configuration items and descriptions are as follows:

# Configuration section for migration from AWS to COS
[migrateAws]
bucket=bucket-aws
accessKeyId=AccessKeyId
accessKeySecret=SecretAccessKey
endPoint=s3.us-east-1.amazonaws.com
prefix=
proxyHost=
proxyPort=

Configuration Item Description
bucket Name of the AWS bucket
accessKeyId Replace AccessKeyId with your SecretId
accessKeySecret Replace SecretAccessKey with your SecretKey
endPoint Address of the AWS endpoint, which must be a domain name instead of region
prefix Prefix of the path to be migrated. If all data in the bucket needs to be migrated, leave the prefix blank
proxyHost If you want to use a proxy for access, enter the proxy IP address
proxyPort Proxy port

3.3.4 Configure a Qiniu data source migrateQiniu

If you migrate from Qiniu to COS, configure this section. The specific configuration items and descriptions are as follows:

# Configuration section for migration from Qiniu to COS
[migrateQiniu]
bucket=bucket-qiniu
accessKeyId=AccessKey
accessKeySecret=SecretKey
endPoint=www.bkt.clouddn.com
prefix=
proxyHost=
proxyPort=

Configuration Item Description
bucket Name of the Qiniu bucket
accessKeyId Replace AccessKey with your SecretId
accessKeySecret Replace SecretKey with your SecretKey
prefix Prefix of the path to be migrated. If all data in the bucket needs to be migrated, leave the prefix blank
proxyHost If you want to use a proxy for access, enter the proxy IP address
proxyPort Proxy port

3.3.5 Configure a URL list data source migrateUrl

If you migrate from a specified URL list to COS, configure this section. The specific configuration items and descriptions are as follows:

# Configuration section for migration from a URL list to COS
[migrateUrl]
urllistPath=D:\\folder\\urllist.txt

Configuration Item Description
urllistPath Address of the URL list, whose content is URL text with one original URL address per line (such as http://aaa.bbb.com/yyy/zzz.txt, no need to add any double quotation marks or other symbols). The address of the URL list must be an absolute path:
• Linux uses a slash (/) as the delimiter, for example, /a/b/c.txt
• Windows uses two backlashes (\) as the delimiter, for example, E:\\a\\b\\c.txt
If a directory is entered, all files under the directory will be treated as URL list files for scan and migration

3.3.6 Configure bucket replication migrateBucketCopy

If you migrate from one COS bucket to another bucket, configure this section. The specific configuration items and descriptions are as follows:

Note：

The account that initiates the migration needs to have permissions to read the source bucket and write to the destination bucket.

# Configuration section for migration from source bucket to destination bucket
[migrateBucketCopy]
srcRegion=ap-shanghai
srcBucketName=examplebucket-1250000000
srcSecretId=COS_SECRETID
srcSecretKey=COS_SECRETKEY
srcCosPath=/

Configuration Item Description
srcRegion Region information of the source bucket. For more information, see Available Regions
srcBucketName Name of the source bucket in the format of <bucketname-appid>. The bucket name must include the APPID, such as examplebucket-1250000000
srcSecretId SecretId of the user who owns the source bucket, which can be viewed in Cloud API Key Management. If the data is owned by the same user, srcSecretId is the same as the SecretId in the common section, otherwise the migration is cross-account bucket copy
srcSecretKey SecretKey of the user who owns the source bucket, which can be viewed in Cloud API Key Management. If the data is owned by the same user, srcSecretKey is the same as the secretKey in the common section, otherwise, the migration is cross-account bucket copy
srcCosPath The COS path to be migrated, meaning files in this path will be migrated to the destination bucket

3.3.7 Configure UpYun data source migrateUpyun
When you migrate from a local system to COS, configure this section. The specific configuration items and descriptions are as follows:

[migrateUpyun]
# Migrate from UpYun
bucket=xxx
# ID of the UpYun operator
accessKeyId=xxx
# Password of the UpYun operator
accessKeySecret=xxx
prefix=
# UpYun sdk restriction, this proxy will be configured as a global proxy
proxyHost=
proxyPort=

Configuration Item Description
bucket Name of the UpYun bucket
accessKeyId Replace with the ID of the UpYun operator
accessKeySecret Replace with the password of the UpYun operator
prefix Prefix of the path to be migrated. If all data in the bucket needs to be migrated, leave the prefix blank
proxyHost If you want to use a proxy for access, enter the proxy IP address
proxyPort Proxy port

### 4. Run the migration tool

#### Windows

Double-click start_migrate.bat to run the tool

#### Linux

1. Read the configuration from the config.ini file by running the following command:

sh start_migrate.sh

2. Read the configuration from command lines for some parameters by running the following command:

sh start_migrate.sh -Dcommon.cosPath=/savepoint0403_10/

Note：

• The tool supports reading configuration items in two ways: command line or configuration file.
• The command line takes priority over the configuration file, i.e., for the same configuration item, parameters in command lines take priority.
• Reading configuration items from command lines allows users to run different migration jobs at the same time, provided that key configuration items (such as bucket name, COS path, source path to be migrated, etc.) in the two jobs are not exactly the same. Concurrent migration can be achieved because different migration jobs are written into different db directories. Please refer to db information in the tool structure above.
• Configuration items are in the format of -D{sectionName}.{sectionKey}={sectionValue}. sectionName is the section name of the configuration file. sectionKey is the name of the configuration item in the section. sectionValue is the value of the configuration item in the section. COS path to which data is migrated to should be in the format of -Dcommon.cosPath=/bbb/ddd.

## Migration mechanism and process

### Migration mechanism

COS migration tool has a status. Successful migrations will be recorded in the format of KV in the leveldb file under the db directory. Before each migration, check whether the path to which data is migrated has been recorded in the db directory. If yes and its attribute is the same as that in db, the migration will be skipped. Otherwise, the migration will be executed. The attribute varies by migration type. For local migration, mtime determines whether to migrate. For migration from other cloud storage services and bucket replication, ETag and length of the source file determine whether to migrate. Thus, we search for records of successful migrations in the db directory rather than in COS. If a file is deleted or modified via COSCMD or the console rather than the migration tool, the migration tool cannot detect this change and the file will not be re-migrated.

### Migration process

1. The configuration file is read, the corresponding configuration section is read according to the migration type, and parameters are checked.
2. The IDs of the files to be migrated are scanned and compared in the db directory according to the specified migration type to determine whether upload is allowed.
3. The execution results are printed out during migration, where inprogress indicates migration is in progress, skip indicates skipped, fail indicates failed, ok indicates succeeded, and condition_not_match indicates file fails to meet migration conditions (such as lastmodified and excludes) and is skipped. Details about the failure can be viewed in the error log. The execution process is shown below:
4. Statistics are printed out after the migration is completed, which include the total number of migrated, failed, and skipped files as well as the amount of time consumed. For failures, check the error log, or rerun the migration job as the migration tool will skip successfully migrated files and retry migrating failed ones. The execution result of a migration job is shown below:

## FAQs

If an exception such as migration failure or execution error occurs when you use COS Migration tool, see COS Migration Tool for troubleshooting.