Often happens with VM instances where the OS is returning spinning via the lsblk value when the host it lives on is SSD.
Resolution
Force SOLR to treat the disks as SSD, thereby overriding the lsblk value, as so:
1. edit /etc/cb/cb.conf for each node in the cluster. 2 change this line from:
SolrDiskType=auto
to
SolrDiskType=ssd
3. restart the cluster.
Additional Information
Issue may occur after reboot of OS
A thread dump capture of solr indicates delay to commit data to disk takes more than 90 seconds, which causes the watchlist window to miss the event. The overloaded disk i/o will stall the solr commit rates.
The max threading and max merge is different per type
HDD - Solr will create maxThreadCount=1 and MaxMergeCount=6
SSD - Solr will create maxThreadCount=4 and MaxMergeCount=11
Note: The OER recommends SSD's to handle the high amount of data ingestion that comes in.