#Scylla Operations Course [Part 4 - Scylla Monitoring]
Disk Scheduling
sstable
- composed of multiple parts, all sharing similar structure "mc--big-"
- TOC- text file for which the components exists for this specific sstable "generation"
- Bloom Filter- provides answer if partition is not stored in sstable
- Statistics - stores different stats about the file - including minimal values used for delta encoding
- Summery - Lookup into the index file "pages" that may contain the partition
- Index - Lookup into the data file "blocks" that contain the partition
- Data- Hold the partition information.
- CompressionInfor- If compression was enabled provide a map of the compressed files in the data file
- Scylla - additional scylla meta information + partition sharding information
While Reading
Single Partition Read path
-Single Page
- we are reading small buffers
- Issues read aheads as sequential read requests from the data file are requested
- Multiple Pages
- cache the readers for the next page request (querier cache)
- Eviction based on - resources / memory / time policy
Memtable / Compactions / Streaming / Repair
- Commitlog - 32 MB files, Pre-Allocating space, recycling commitlogs (for efficiency)
Data Scheduling
