42 lines
1.8 KiB
Markdown
42 lines
1.8 KiB
Markdown
---
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layout: "docs"
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page_title: "Frequently Asked Questions"
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sidebar_current: "docs-faq"
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---
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# Frequently Asked Questions
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## Q: Why is virtual memory usage high?
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Consul makes use of [LMDB](http://symas.com/mdb/) internally for various data
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storage purposes. LMDB relies on using memory-mapping, a technique in which
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a sparse file is represented as a contiguous range of memory. Consul configures
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high limits for these file sizes, and as a result relies on a large chunks of
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virtual memory to be allocated. However, in practice the limits are much larger
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than any realistic deployment of Consul would ever use, and the resident memory or
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physical memory used is much lower.
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## Q: What is Checkpoint? / Does Consul call home?
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Consul makes use of a HashiCorp service called [Checkpoint](http://checkpoint.hashicorp.com)
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which is used to check for updates and critical security bulletins.
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Only anonymous information is sent to Checkpoint, and cannot be used to
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identify the user or host. An anonymous ID is sent which helps de-duplicate
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warning messages and can be disabled. Using the Checkpoint service is optional
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and can be disabled.
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See [`disable_anonymous_signature`](/docs/agent/options.html#disable_anonymous_signature)
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and [`disable_update_check`](/docs/agent/options.html#disable_update_check).
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## Q: How does Atlas integration work?
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Consul makes use of a HashiCorp service called [SCADA](http://scada.hashicorp.com)
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which stands for Supervisory Control And Data Acquisition. The SCADA system allows
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clients to maintain a long-running connection to Atlas which is used to make requests
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to Consul agents for features like the dashboard and auto joining. Standard ACLs can
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be applied to the SCADA connection, which has no enhanced or elevated privileges.
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Using the SCADA service is optional and only enabled by opt-in.
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See the [Atlas integration guide](/docs/guides/atlas.html).
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