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Torch Log Service

Product Overview

Limits

Resources limits

The quota limits for basic Torch Log Service(TLS) resources are as follows.

Items	Description	Note
Number of log projects	Each account can create up to 100 log projects per region by default.	For quota adjustments, see Apply for resource quota.
Number of log topics	By default, up to 200 log topics can be created in each log project.	For quota adjustments, see Apply for resource quota.
Number of log shards	When creating a log topic, up to 10 log shards can be created by default. After creating a log topic, you can increase the number of shards by splitting shards, up to a maximum of 256 read-write shards.	For quota adjustments, see Apply for resource quota.
Host group	By default, each account can create up to 200 host groups per region. Each host group can include up to 200 IP addresses by default.	For quota adjustments, see Apply for resource quota.
Dashboard	By default, a maximum of 50 dashboards can be created in each log project. The total number of filters, variables, and charts in each dashboard must not exceed 50.	For quota adjustments, see Apply for resource quota.
Data transformation	By default, up to 100 transformation tasks can be created per log project. By default, up to 30 transformation tasks can be created per log topic.	For quota adjustments, see Apply for resource quota.
Data consumption	By default, a maximum of 150 consumer groups can be created per log project.	For quota adjustments, see Apply for resource quota.
Alarm	By default, up to 100 alarm policies can be created per log project. By default, up to 10 alarm policies can be created per log topic.	For quota adjustments, see Apply for resource quota.
Log storage period	The log storage time can be set from 1 to 3650 days. If you set 3650 days, the storage time becomes permanent.	/

Flow control limits

Read and write capacity limits

Account level

Each VolcanoEngine account provides a certain read and write capacity. For details, see the table below.

Notice

If topic read and write needs exceed the read and write capacity of log shard, the service will continue as much as possible. However, quality can not be guaranteed.

Items	Limits
Read QPS	20000 times/second
Write QPS	20000 times/second
Read traffic	1 GiB/s
Write traffic	1 GiB/s

Shard level

Each log shard provides a certain level of read and write capability. For detailed information, please refer to the table below.

Notice

This is a non-mandatory requirement. When data read/write operations exceed the read/write capacity of the log shard, the system will provide service to the best of its ability, but does not guarantee service quality.

Limitations	Limitation
Read QPS	100 times per second
Write QPS	500 times per second
Read traffic	20 MiB/s
Write traffic	5 MiB/s

Other flow control limits

Each VolcanoEngine account also defines some additional TLS flow control limits. For details, see the table below.

Items	Limits
LogCollector configuration retrieve QPS	4000 times/second
LogCollector heartbeat report QPS	2000 times/second
Consumer group heartbeat report QPS	2000 times/second
Consumer group checkpoint QPS	500 times/second
Dashboard subscription QPM	1 time/minute
Control interface call QPS	20 times/second

LogCollector limits

When collecting log data using LogCollector, note its installation environment and collection behaviors. For details, see LogCollector limits.

Query and analysis limits

In TLS, the following limits apply to log query and analysis actions.

Query limits

Limit items	Description	Note
Number of characters per single field	After tokenizing logs, the length of each token must not exceed 255 bytes.	If the limit is exceeded, this log can not be queried by keywords. However, the server still retains the complete log data.
Query statement length	The maximum length for a single search statement is 4,096 characters.	/
Phrase query	For phrase queries, you can select up to 10,000 logs for phrase matching.
Operation concurrency	Standard storage: The maximum number of concurrent operations under one single project is 100. The maximum number of concurrent operations under one single topic is 15. Infrequent access storage: a single project supports up to 10 concurrent operations. Notice When the log query range includes both standard and infrequent access storage, the operation concurrency of infrequent access storage applies.	/
Timeout	The query operation timeout is 55 seconds.	/
Fuzzy query	During fuzzy queries, TLS queries up to 100 matching words. Then TLS returns all logs containing those words that meet the query conditions.	/
Keyword search	When querying keywords, you can specify up to 30 query conditions each time.	/
Return results	By default, each query returns up to 100 results.	/
Query result sequence	By default, log display starts from the latest logs. The time can be set precisely down to seconds or milliseconds.	/
Single log content display	Limited by web browser performance, for logs that exceed 10,000 characters, the TLS only processes the first 10,000 characters for DOM tokenization.	If the log data exceeds 10,000 characters, the console displays "Log data exceeds 10,000 characters. The display of partial logs may be downgraded."

Analysis limits

Limit items	Description
Data volume	A single shard supports analyzing up to 1 GiB of data per operation.
Query and analysis statement length	The maximum length of a single query and analysis statement is 50,000 characters. Within the statement, the maximum length of the query part is 4,096 characters.
Field value size	The maximum size of a single field value is 16KB, i.e., 16,384 bytes. If exceeded, the excess part will not be analyzed. The default maximum length for field values in TLS is 2,048 bytes, i.e., 2 KB. If you need to adjust the maximum length of field values, you can set maximum length for statistic fields. For specific steps, see Set the maximum length of the field. Notice Updating the configuration only affects incremental data.
Operation concurrency	Standard storage: The maximum number of concurrent operations under one single project is 100. The maximum number of concurrent operations under one single topic is 15. Infrequent access storage: The maximum number of concurrent operations under one single project is 2. Notice When the logs that need query and analysis includes both standard storage and infrequent access storage, the concurrency limit of infrequent access storage applies.
Data activation mechanism	Analysis functions only apply to data that is written after the statistics function is enabled. For fields without enabled statistics function, the SQL analysis result shows as empty.
Data activation mechanism		SQL analysis only applies to data that corresponds to the latest index version. Data before index modification can be queried but is excluded from SQL analysis.
Timeout	The query operation timeout is 55 seconds.
Number of results	By default, 100 results are returned per analysis. If you need to return more data, use LIMIT syntax. In this case, up to 100,000 results can be returned.

Copilot limits

Items	Description
New session count	Each account supports up to 1000 new sessions per region.
Maximum length per query	The maximum length per query is 2000 characters.
History sessions retention period	The maximum retention period for historical sessions is 30 days. If the number of sessions exceeds the maximum limit, historical sessions may be deleted before reaching the maximum retention period.
Maximum context rounds per inference	The maximum number of historical conversation rounds per inference is 20. To improve answer accuracy, clear the context before asking different questions.

Data transformation limits

Limit items	Description	Note
Number of tasks	A maximum of 100 data transformation tasks can be created per log project. A maximum of 30 data transformation tasks can be created per log topic. All tasks that are displayed on the page are included, regardless of their status. Notice Tasks that are in suspended or completed statuses also occupy the quota. Therefore, if you ensure that you no longer need some task, clear the task list promptly to release quota quantities. For more information, see the following documents: Manage data processing tasks.	For quota adjustments, refer to Apply for resource quotas.
Target log topic number	You can configure up to 20 different log topics in one data transformation task to store processed data.	For quota adjustments, refer to Apply for resource quotas.
Execution preview	The execution preview function for data transformation is used for online debugging of data transformation code. Note the following restrictions when conducting execution preview: In a single request, test data or raw logs can not exceed 20 entries. Otherwise, the preview request will return an error. For per request, a maximum of 100 transformation results can be returned.	/
Transformation performance	The overall transformation task rate is calculated as the number of shards read and written by the source log topic * 1MiB/s (uncompressed traffic). Meanwhile, the overall transformation rate is also limited by factors such as transformation rule complexity, source log topic concurrency, source log topic consumption rate, and target log topic write speed. For more details, refer to the documentation.Performance Influencing Factors .	/

Scheduled SQL analysis limits

Category	Limit items	Description
Resource management	Number of scheduled SQL analysis tasks	A maximum of 100 SQL analysis tasks can be created per log project. A maximum of 15 scheduled SQL analysis tasks can be created per source log topic.
		Delete scheduled SQL analysis task	The trace functionality of TLS depends on the normal running of the scheduled SQL analysis task. To ensure the availability of trace storage, do not conduct any manual changes to SQL analysis tasks that correspond to trace storage, such as changing configurations or deleting tasks. If you need to modify the trace storage configuration or disable trace storage, proceed on pages that relate to trace storage.
		Execution history	Task execution record can be retained for up to 7 days. We recommend that you add scheduled SQL analysis tasks to identify issues promptly.
		Task scheduling concurrency	A single account supports 10 concurrent executions.
Data writing	Data delay	When data delay happens, the risk that data fails to be retrieved may exist. That is to say, if data for a certain time arrives after the corresponding scheduling instance finishes, it will not be queried in the next scheduling instance.
		Instance concurrency	Only one scheduling instance per task can be in the scheduling state at a time.
		Write failure retry	If data writing fails, the system retries 3 times thereafter. The interval between every two retries is 60 seconds. After 3 consecutive write failures, the instance status will change to execution failed. We recommend that you add scheduled SQL analysis tasks to promptly detect issues.

Log shipping limits

TOS shipping limits

Limitations			Description
Account			To deliver logs across Volcengine accounts, cross-account delivery permissions must be configured.
Region			Cross-region log delivery is not supported, that is, the log topic and the TOS bucket should be located in the same region.
Field			When delivering logs, the JSON format by default delivers all fields, including metadata fields such as __source__, while the CSV format allows you to configure the list of fields to be delivered.
Resource quotas	Number of delivery configurations	Each log topic can have up to 10 TOS delivery configurations.
		Query delivery tasks	You can only query delivery tasks triggered within the past 3 days.
		Delivery intervals	The delivery time interval can be set to 60 to 900 seconds.
		Size of delivered data	Delivered data packets must be between 5 and 256 MiB in size.

Kafka shipping limits

Limitations	Description
Account	To deliver logs across Volcengine accounts, cross-account delivery permissions must be configured.
Region	Cross-region log delivery is not supported, that is, both the log topic and the Kafka instance should be located in the same region.
Resource quotas	Each log topic can have up to 10 Kafka delivery configurations.

Alarm limits

Category	Limitations	Description
Alarm monitoring	Number of alarm policies	Up to 100 alarm policies can be created in each project. Up to 10 alarm policies can be created in each log topic.
		Length of field value	If the value of a field exceeds 1024 characters, only the first 1024 characters are used for analysis.
		Time range of query and analysis	The time span of each query and analysis statement must not exceed 24 hours.
		Query and analysis results	When there is no set operation, the monitoring task selects up to the first 1000 rows of data from the query and analysis results for alert triggering; when there is a set operation, the monitoring task selects up to the first 1000 rows of data from the set operation results for alert triggering. When associating three monitoring sets, the monitoring task selects up to the first 100 rows of data from each query and analysis result for set operations.
		Alert expression length	The length range of an alarm expression is 4 to 1024 characters.
notification management	Number of notification groups	Each region can create up to 100 notification groups.
		Number of notification channels	A maximum of 10 notification channels can be added to each notification group.
		Notification content	The maximum length of notification content is 4096 Chinese characters.
		Channel notification frequency	The notification frequency limits for each alert channel of TLS are as follows. Email: unlimited. SMS: The maximum frequency of SMS alert notifications for the same mobile phone number is 10 messages per minute, 100 messages per hour, and 300 messages per day. Phone: The maximum frequency of voice alert notifications for the same mobile phone number is 10 per minute, 100 per hour, and 300 per day. Notice Only domestic (+86) phone numbers are supported.

Resource naming limits

TLS includes resources such as project, topic, external data sources, dashboards, collection configurations, scheduled SQL tasks, transformation tasks, trace instances, and delivery tasks. The naming rules are as follows:

Resources	Description
Project, Topic, external data source	Length must be between 3 and 64 characters. Only supports Chinese characters, lowercase letters, digits, underscores (_), and hyphens (-). Can not start or end with an underscore (_) or hyphen (-). Cannot start with the following reserved prefixes: tls_, tls-log-collector-topic_, tls-service-log_, tls-service-project_, tls-service-topic_, tls-trace_, tls-trace-source_, volc_, tos_, CDN_, cfw_, dbw_, dbw-hide_, fw_center_, mcs_, NAS_, nta_, vke_, volc_ECS_, VPC_, vpn_, waf_, volc_ipsec_log, etc.
Alarm policy	Length must be between 3 and 255 characters. Supports only Chinese characters, uppercase and lowercase letters, numbers, spaces, and most special characters. Can not start or end with a space. English double quotation marks (") are not supported.
Other resources except project, topic, external data sources, and alarm policies	Length must be between 3 and 64 characters. Supports only Chinese characters, letters, numbers, underscores (_), and hyphens (-). Can not start or end with a hyphen (-). Can not start with the following reserved prefixes: tls_, tls-log-collector-topic_, tls-service-log_, tls-service-project_, tls-service-topic_, tls-trace_, tls-trace-source_, volc_, tos_, CDN_, cfw_, dbw_, dbw-hide_, fw_center_, mcs_, NAS_, nta_, vke_, volc_ECS_, VPC_, vpn_, waf_, volc_ipsec_log, etc.

Last updated: 2025.12.03 18:42:01