首先说一下这个3节点MongoDB集群各个维度的数据规模：
1、dataSize: 1.9T
2、storageSize: 600G
3、全量备份-加压缩开关：186G，耗时 8h
4、全量备份-不加压缩开关：1.8T，耗时 4h27m
具体导出的语法比较简单，此处不再赘述，本文重点描述导入的优化过程，最后给出导入的最佳实践。
■ 2023-09-13T20:00 第1次4并发导入测试
mongorestore --port=20000 -uadmin -p'passwd' --authenticationDatabase=admin --numInsertionWorkersPerCollection=4 --bypassDocumentValidation -d likingtest /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest >> 10.2.2.2.log 2>&1 &
tail -100f /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/10.2.2.2.log
以上导入：
2023-09-13T21:59:55.452+0800 The --db and --collection flags are deprecated for this use-case; please use --nsInclude instead, i.e. with --nsInclude=${DATABASE}.${COLLECTION}
2023-09-13T21:59:55.452+0800 building a list of collections to restore from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest dir
2023-09-13T21:59:55.466+0800 reading metadata for likingtest.oprceConfiguration from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/oprceConfiguration.metadata.json
2023-09-13T21:59:55.478+0800 reading metadata for likingtest.oprceDataObj from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/oprceDataObj.metadata.json
2023-09-13T21:59:55.491+0800 reading metadata for likingtest.oprcesDataObjInit from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/oprcesDataObjInit.metadata.json
2023-09-13T21:59:55.503+0800 reading metadata for likingtest.role from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/role.metadata.json
2023-09-13T21:59:55.508+0800 reading metadata for likingtest.activityConfiguration from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/activityConfiguration.metadata.json
2023-09-13T21:59:55.511+0800 reading metadata for likingtest.history_task from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/history_task.metadata.json
2023-09-13T21:59:55.512+0800 reading metadata for likingtest.resOutRelDataSnapshot from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/resOutRelDataSnapshot.metadata.json
2023-09-13T21:59:55.520+0800 reading metadata for likingtest.snapshotResource from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/snapshotResource.metadata.json
2023-09-13T21:59:55.524+0800 reading metadata for likingtest.oprceDataObjDraft from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/oprceDataObjDraft.metadata.json
2023-09-13T21:59:55.526+0800 reading metadata for likingtest.oprceDataObjInit from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/oprceDataObjInit.metadata.json
2023-09-13T21:59:55.761+0800 restoring likingtest.snapshotResource from /u01/nfs/xxxxx_mongodb/10.1.1.1/20230913/likingtest/snapshotResource.bson
...
2023-09-13T22:00:01.451+0800 [........................] likingtest.oprceDataObj 408MB/1205GB (0.0%)
...
2023-09-13T21:59:58.323+0800 finished restoring likingtest.oprceDataObjDraft (1559 documents, 0 failures)
2023-09-13T22:00:01.034+0800 finished restoring likingtest.resOutRelDataSnapshot (34426 documents, 0 failures)
2023-09-13T22:00:01.559+0800 finished restoring likingtest.history_task (3629 documents, 0 failures)
2023-09-13T22:00:02.086+0800 finished restoring likingtest.activityConfiguration (974 documents, 0 failures)
2023-09-13T22:00:02.293+0800 finished restoring likingtest.oprceConfiguration (162 documents, 0 failures)
2023-09-13T22:00:02.529+0800 finished restoring likingtest.oprcesDataObjInit (4 documents, 0 failures)
2023-09-13T22:00:02.857+0800 finished restoring likingtest.role (10 documents, 0 failures)
2023-09-13T22:00:29.153+0800 [########################] likingtest.snapshotResource 2.04GB/2.04GB (100.0%)
2023-09-13T22:00:29.155+0800 finished restoring likingtest.snapshotResource (50320 documents, 0 failures)
...
2023-09-14T00:18:58.451+0800 [############............] likingtest.oprceDataObj 651GB/1205GB (54.0%)
2023-09-14T00:18:59.857+0800 [########################] likingtest.oprceDataObjInit 635GB/635GB (100.0%)
2023-09-14T00:18:59.888+0800 finished restoring likingtest.oprceDataObjInit (43776648 documents, 0 failures)
...
2023-09-14T02:05:58.904+0800 [########################] likingtest.oprceDataObj 1205GB/1205GB (100.0%)
2023-09-14T02:05:58.937+0800 finished restoring likingtest.oprceDataObj (53311330 documents, 0 failures)
2023-09-14T02:05:58.945+0800 no indexes to restore for collection likingtest.activityConfiguration
2023-09-14T02:05:58.945+0800 no indexes to restore for collection likingtest.history_task
2023-09-14T02:05:58.945+0800 restoring indexes for collection likingtest.oprcesDataObjInit from metadata
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"flowId_1_activityConfiguration.activityNameEn_1", "ns":"likingtest.oprcesDataObjInit", "v":2}, Key:primitive.D{primitive.E{Key:"flowId", Value:1}, primitive.E{Key:"activityConfiguration.activityNameEn", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"oprceInfo.oprceInstID_1_activityInfo.activityInstID_1_workitemInfo.workItemID_1", "ns":"likingtest.oprcesDataObjInit", "v":2}, Key:primitive.D{primitive.E{Key:"oprceInfo.oprceInstID", Value:1}, primitive.E{Key:"activityInfo.activityInstID", Value:1}, primitive.E{Key:"workitemInfo.workItemID", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 no indexes to restore for collection likingtest.role
2023-09-14T02:05:58.976+0800 no indexes to restore for collection likingtest.snapshotResource
2023-09-14T02:05:58.976+0800 no indexes to restore for collection likingtest.oprceDataObjDraft
2023-09-14T02:05:58.976+0800 restoring indexes for collection likingtest.oprceDataObjInit from metadata
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"oprceInfo.oprceInstID_1_activityInfo.activityInstID_1_workitemInfo.workItemID_1", "ns":"likingtest.oprceDataObjInit", "v":2}, Key:primitive.D{primitive.E{Key:"oprceInfo.oprceInstID", Value:1}, primitive.E{Key:"activityInfo.activityInstID", Value:1}, primitive.E{Key:"workitemInfo.workItemID", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"flowNo_1", "ns":"likingtest.oprceDataObjInit", "v":2}, Key:primitive.D{primitive.E{Key:"flowNo", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 no indexes to restore for collection likingtest.oprceConfiguration
2023-09-14T02:05:58.976+0800 no indexes to restore for collection likingtest.resOutRelDataSnapshot
2023-09-14T02:05:58.976+0800 restoring indexes for collection likingtest.oprceDataObj from metadata
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"flowId_1_activityConfiguration.activityNameEn_1", "ns":"likingtest.oprceDataObj", "v":2}, Key:primitive.D{primitive.E{Key:"flowId", Value:1}, primitive.E{Key:"activityConfiguration.activityNameEn",Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"flowNo_1", "ns":"likingtest.oprceDataObj", "v":2}, Key:primitive.D{primitive.E{Key:"flowNo", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"oprceInfo.oprceInstID_1_activityInfo.activityInstID_1_workitemInfo.workItemID_1", "ns":"likingtest.oprceDataObj", "v":2}, Key:primitive.D{primitive.E{Key:"oprceInfo.oprceInstID", Value:1}, primitive.E{Key:"activityInfo.activityInstID", Value:1}, primitive.E{Key:"workitemInfo.workItemID", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T02:05:58.976+0800 index: &idx.IndexDocument{Options:primitive.M{"name":"flowId_1_activityConfiguration.activityNameEn_1", "ns":"likingtest.oprceDataObjInit", "v":2}, Key:primitive.D{primitive.E{Key:"flowId", Value:1}, primitive.E{Key:"activityConfiguration.activityNameEn", Value:1}}, PartialFilterExpression:primitive.D(nil)}
2023-09-14T03:45:47.152+0800 97179062 document(s) restored successfully. 0 document(s) failed to restore.
可见：
1、配置并发参数 --numInsertionWorkersPerCollection=4 和 检查参数 bypassDocumentValidation 后，restore速度大大提升，1.2T 的一个大集合 oprceDataObj，由原来默认restore方式约 12h，降为：4h
2、restore完所有数据以后，最后再restore索引，restore索引还是需要一定的时间，本次耗时：1h40m【注：实际没有成功，索引并未生效】
3、新版本的 -d -c 参数需统一修改为：--nsInclude --nsFrom= --nsTo=
■ 2023-09-14T10:40 第2次8并发导入测试
mongorestore --port=20000 -uadmin -p'passwd' --authenticationDatabase=admin --numInsertionWorkersPerCollection=8 --bypassDocumentValidation -d likingtest /u01/nfs/xxxxx_mongodb/10.1.1.1/20230914/likingtest >> 10.2.2.2.log 2>&1 &
tail -100f /u01/nfs/xxxxx_mongodb/10.1.1.1/20230914/10.2.2.2.log
---
2023-09-14T10:40:45.492+0800 The --db and --collection flags are deprecated for this use-case; please use --nsInclude instead, i.e. with --nsInclude=${DATABASE}.${COLLECTION}
...
2023-09-14T10:40:48.493+0800 [........................] likingtest.oprceDataObj 112MB/1208GB (0.0%)
...
2023-09-14T12:57:34.859+0800 [########################] likingtest.oprceDataObj 1208GB/1208GB (100.0%)
2023-09-14T12:57:34.867+0800 finished restoring likingtest.oprceDataObj (53413481 documents, 0 failures)
可见：
1、配置并发参数 --numInsertionWorkersPerCollection=8 和 检查参数 --bypassDocumentValidation 后，restore速度再次大大提升，1.2T的一个大集合 oprceDataObj，由原来默认restore方式约 12h，降为：2h17m
2、本次恢复采用nfs备份恢复，一台8C的虚机，8并发恢复时cpu占用约40%，网络接收速度300MB/s左右，本地磁盘写入速度在30-200MB/s左右，可见网络带段不是瓶颈。可以预见，如果采用更高的主机配置，尤其是IO更好的磁盘，resotore时间必将更少。
■ 2023-09-14T16:10 第3次12并发导入测试
【注意】由于新版本mongorestore摒弃了-d -c参数，虽然可用但使用不够灵活，因此需使用新参数--nsInclude，对于该参数的使用，摸索了多次才找到使用的限制条件，即 directory 必须为数据库备份的根目录/上一级目录，而不是 数据库目录！即类似 dumpdir/20230914，而不是 dumpdir/20230914/database！这是一个巨大的坑，切记！当然，这个目录下一定不能有其他不可识别的文件，否则也会报错。
mongorestore --port=20000 -uadmin -p'passwd' --authenticationDatabase=admin --numInsertionWorkersPerCollection=12 --bypassDocumentValidation --nsInclude="likingtest.*" /u01/nfs/xxxxx_mongodb/10.1.1.1/20230914 > 20230914.10.2.2.2-3.log 2>&1 &
tail -100f /u01/nfs/xxxxx_mongodb/10.1.1.1/20230914.10.2.2.2-3.log
---
2023-09-14T16:10:19.245+0800 preparing collections to restore from
...
2023-09-14T18:18:18.996+0800 [########################] likingtest.oprceDataObj 1208GB/1208GB (100.0%)
2023-09-14T18:18:19.014+0800 finished restoring likingtest.oprceDataObj (53413481 documents, 0 failures)
可见：
1、并发由 8 增至 12 并无效率提升，结论是 6-8 个并发就可以，这一点与oracle的并发导入设置为 6 基本是最佳实践类似。
2、本次恢复采用nfs备份恢复，一台8C的虚机，12并发恢复时cpu占用约60%，网络接收速度300MB/s左右，本地磁盘写入速度在30-500MB/s左右，可见网络带段不是瓶颈。可以预见，如果采用更高的主机配置，尤其是IO更好的磁盘，resotore时间必将更少。
3、关于索引的restore，restore时首先恢复数据，最后再创建索引，比较大的集合的索引创建还是需要较多的时间：
currentOpTime: '2023-09-14T20:23:59.435+08:00',
...
command: {
createIndexes: 'oprceDataObj',
indexes: [
{
key: { flowId: 1, 'activityConfiguration.activityNameEn': 1 },
name: 'flowId_1_activityConfiguration.activityNameEn_1',
ns: 'likingtest.oprceDataObj'
},
{
key: { flowNo: 1 },
name: 'flowNo_1',
ns: 'likingtest.oprceDataObj'
},
{
key: {
'oprceInfo.oprceInstID': 1,
'activityInfo.activityInstID': 1,
'workitemInfo.workItemID': 1
},
name: 'oprceInfo.oprceInstID_1_activityInfo.activityInstID_1_workitemInfo.workItemID_1',
ns: 'likingtest.oprceDataObj'
}
],
.....
currentOpTime: '2023-09-14T20:23:59.489+08:00',
...
command: {
createIndexes: 'oprcesDataObjInit',
indexes: [
{
key: { flowId: 1, 'activityConfiguration.activityNameEn': 1 },
name: 'flowId_1_activityConfiguration.activityNameEn_1',
ns: 'likingtest.oprcesDataObjInit'
},
{
key: {
'oprceInfo.oprceInstID': 1,
'activityInfo.activityInstID': 1,
'workitemInfo.workItemID': 1
},
name: 'oprceInfo.oprceInstID_1_activityInfo.activityInstID_1_workitemInfo.workItemID_1',
ns: 'likingtest.oprcesDataObjInit'
}
],
......第二天再看，还没创建完索引：
currentOpTime: '2023-09-15T09:16:16.460+08:00',
effectiveUsers: [ { user: 'admin', db: 'admin' } ],
runBy: [ { user: '__system', db: 'local' } ],
threaded: true,
opid: 'shard1:11312917',
lsid: {
id: new UUID("e78379ff-9664-46b1-9e87-2bdd4abc5c5f"),
uid: Binary.createFromBase64("O0CMtIVItQN4IsEOsJdrPL8s7jv5xwh5a/A5Qfvs2A8=", 0)
},
secs_running: Long("53877"),
microsecs_running: Long("53877330742"),
op: 'command',
ns: 'likingtest.oprcesDataObjInit',
redacted: false,
command: {
createIndexes: 'oprcesDataObjInit',
......第二天满24h，还没创建完索引：
currentOpTime: '2023-09-15T18:55:16.877+08:00',
effectiveUsers: [ { user: 'admin', db: 'admin' } ],
runBy: [ { user: '__system', db: 'local' } ],
threaded: true,
opid: 'shard1:11312917',
lsid: {
id: new UUID("e78379ff-9664-46b1-9e87-2bdd4abc5c5f"),
uid: Binary.createFromBase64("O0CMtIVItQN4IsEOsJdrPL8s7jv5xwh5a/A5Qfvs2A8=", 0)
},
secs_running: Long("88617"),
microsecs_running: Long("88617747875"),
op: 'command',
ns: 'likingtest.oprcesDataObjInit',
redacted: false,
command: {
createIndexes: 'oprcesDataObjInit',
indexes: [
{
key: { flowId: 1, 'activityConfiguration.activityNameEn': 1 },
name: 'flowId_1_activityConfiguration.activityNameEn_1',
ns: 'likingtest.oprcesDataObjInit'
},
以上可见，mongorestore 导入数据库的数据效率目前是基本可控、可接受的，至少对于1.2T的大集合是可以接受的，但是最后的索引创建实在过于缓慢，且没有找到合适的解决办法：索引需多并发执行创建，且确保索引生效，本次索引创建最后并未生效
■ 2023-09-15T19:02 第4次10并发导入测试，不恢复索引
mongorestore --port=20000 -uadmin -p'passwd' --authenticationDatabase=admin --numInsertionWorkersPerCollection=10 --bypassDocumentValidation --nsInclude="likingtest.*" --nsFrom="likingtest.*" --nsTo="likingtest.*" --noIndexRestore /u01/nfs/xxxxx_mongodb/10.1.1.1/20230914 > 20230914.10.2.2.2-4.log 2>&1 &
tail -100f /u01/nfs/xxxxx_mongodb/10.1.1.1/20230914.10.2.2.2-4.log
2023-09-15T19:02:59.747+0800 preparing collections to restore from
...
2023-09-15T21:24:36.145+0800 [########################] likingtest.oprceDataObj 1208GB/1208GB (100.0%)
2023-09-15T21:24:36.161+0800 finished restoring likingtest.oprceDataObj (53413481 documents, 0 failures)
2023-09-15T21:24:36.165+0800 97367732 document(s) restored successfully. 0 document(s) failed to restore.
以上可见，耗时：2h22m
结论
1、restore 时需设置大数据量 collection 多并发导入：--numInsertionWorkersPerCollection=8
2、不恢复索引：--noIndexRestore
3、数据恢复后，后台创建索引：本站搜索"MongoDB 重建索引"