Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.
Grafana Loki Storage
High level storage overview here
Grafana Loki needs to store two different types of data: chunks and indexes.
Loki receives logs in separate streams, where each stream is uniquely identified by its tenant ID and its set of labels. As log entries from a stream arrive, they are compressed as “chunks” and saved in the chunks store. See chunk format for how chunks are stored internally.
The index stores each stream’s label set and links them to the individual chunks.
Refer to Loki’s configuration for details on how to configure the storage and the index.
For more information:
Supported Stores
The following are supported for the index:
- Single Store (boltdb-shipper) - Recommended for 2.0 and newer index store which stores boltdb index files in the object store
- Amazon DynamoDB
- Google Bigtable
- Apache Cassandra
- BoltDB (doesn’t work when clustering Loki)
The following are supported for the chunks:
- Amazon DynamoDB
- Google Bigtable
- Apache Cassandra
- Amazon S3
- Google Cloud Storage
- Filesystem (please read more about the filesystem to understand the pros/cons before using with production data)
- Baidu Object Storage
Cloud Storage Permissions
S3
When using S3 as object storage, the following permissions are needed:
s3:ListBucket
s3:PutObject
s3:GetObject
s3:DeleteObject
(if running the Single Store (boltdb-shipper) compactor)
Resources: arn:aws:s3:::<bucket_name>
, arn:aws:s3:::<bucket_name>/*
DynamoDB
When using DynamoDB for the index, the following permissions are needed:
dynamodb:BatchGetItem
dynamodb:BatchWriteItem
dynamodb:DeleteItem
dynamodb:DescribeTable
dynamodb:GetItem
dynamodb:ListTagsOfResource
dynamodb:PutItem
dynamodb:Query
dynamodb:TagResource
dynamodb:UntagResource
dynamodb:UpdateItem
dynamodb:UpdateTable
dynamodb:CreateTable
dynamodb:DeleteTable
(iftable_manager.retention_period
is more than 0s)
Resources: arn:aws:dynamodb:<aws_region>:<aws_account_id>:table/<prefix>*
dynamodb:ListTables
Resources: *
AutoScaling
If you enable autoscaling from table manager, the following permissions are needed:
Application Autoscaling
application-autoscaling:DescribeScalableTargets
application-autoscaling:DescribeScalingPolicies
application-autoscaling:RegisterScalableTarget
application-autoscaling:DeregisterScalableTarget
application-autoscaling:PutScalingPolicy
application-autoscaling:DeleteScalingPolicy
Resources: *
IAM
iam:GetRole
iam:PassRole
Resources: arn:aws:iam::<aws_account_id>:role/<role_name>
Chunk Format
-------------------------------------------------------------------
| | |
| MagicNumber(4b) | version(1b) |
| | |
-------------------------------------------------------------------
| block-1 bytes | checksum (4b) |
-------------------------------------------------------------------
| block-2 bytes | checksum (4b) |
-------------------------------------------------------------------
| block-n bytes | checksum (4b) |
-------------------------------------------------------------------
| #blocks (uvarint) |
-------------------------------------------------------------------
| #entries(uvarint) | mint, maxt (varint) | offset, len (uvarint) |
-------------------------------------------------------------------
| #entries(uvarint) | mint, maxt (varint) | offset, len (uvarint) |
-------------------------------------------------------------------
| #entries(uvarint) | mint, maxt (varint) | offset, len (uvarint) |
-------------------------------------------------------------------
| #entries(uvarint) | mint, maxt (varint) | offset, len (uvarint) |
-------------------------------------------------------------------
| checksum(from #blocks) |
-------------------------------------------------------------------
| metasOffset - offset to the point with #blocks |
-------------------------------------------------------------------