Knowledge Base¶

• Scylla Seed Nodes - Introduction on the purpose and role of Seed Nodes in Scylla as well as configuration tips.

• Compaction - To free up disk space and speed up reads, Scylla must do compaction operations.

• DPDK mode - Learn to select and configure networking for DPDK mode

• POSIX networking for Scylla - Scylla’s POSIX mode works on all physical and virtual network devices and is useful for development work.

• System Limits - Outlines the system limits which should be set or removed

• Run Scylla as a custom user:group - Configure the Scylla and supporting services to run as a custom user:group.

• How to Set up a Swap Space Using a File - Outlines the steps you need to take to set up a swap space.

• Gossip in Scylla - Scylla, like Cassandra, uses a type of protocol called “gossip” to exchange metadata about the identities of nodes in a cluster. Here’s how it works behind the scenes.

• Scylla consistency quiz for administrators - How much do you know about NoSQL, from the administrator point of view?

• Scylla Memory Usage - Short explanation how Scylla manages memory

• Scylla Nodes are Unresponsive - How to handle swap in Scylla

• CQL Query Does Not Display Entire Result Set - What to do when a CQL query doesn’t display the entire result set.

• Snapshots and Disk Utilization - How snapshots affect disk utilization

• Scylla Snapshots - What Scylla snapshots are, what they are used for, and how they get created and removed.

• How does Scylla LWT Differ from Apache Cassandra ? - How does Scylla’s implementation of lightweight transactions differ from Apache Cassandra?

• If a query does not reveal enough results

• How to Change gc_grace_seconds for a Table - How to change the gc_grace_seconds parameter and prevent data resurrection.

• How to flush old tombstones from a table - How to remove old tombstones from SSTables.

• Increase Cache to Avoid Non-paged Queries - How to increase the permissions_cache_max_entries setting.

• How to Safely Increase the Replication Factor

• Facts about TTL, Compaction, and gc_grace_seconds

Note: The KB article for social readers has been removed. Instead, please look at lessons on Scylla University or the Care Pet example

• NTP configuration for Scylla - Scylla depends on an accurate system clock. Learn to configure NTP for your data store and applications.

• Scylla and Spark integration - How to run an example Spark application that uses Scylla to store data?

• Map CPUs to Scylla Shards - Mapping between CPUs and Scylla shards

• Recreate RAID devices - How to recreate your RAID devices without running scylla-setup

• Configure Scylla Networking with Multiple NIC/IP Combinations - examples for setting the different IP addresses in scylla.yaml

• Updating the Mode in perftune.yaml After a ScyllaDB Upgrade

• Kafka Sink Connector Quickstart

• Kafka Sink Connector Configuration

• Using the perf utility with Scylla - Using the perf utility to analyze Scylla

• Debug your database with Flame Graphs - How to setup and run a Flame Graph

• Decoding Stack Traces - How to decode stack traces in Scylla Logs

• Counting all rows in a table - Why counting all rows in a table often leads to a timeout