On 8/4/23 09:56, Jayesh Shende wrote:
Using: Solr 8.11.2 with rhel9
Currently using "solr.NRTCachingDirectoryFactory" for a collection,
the collection has grown big in size, but don't want to add more RAM to
machine(AWS),
I can increase IOPS and througput for data volume.
Was thinking of using "solr.NIOFSDirectoryFactory",
but wanted to know, how will it impact to existing collection?
May be it is just a way to read index files, but to be sure, will it
affect my existing indexed data?
It's generally not a good idea to explicitly configure the directory
factory. That should only be done in very unusual circumstances. Your
situation probably does not qualify.
Remove any config for that and let Solr/Lucene pick the class that's
best for the environment. It will probably choose
NRTCachingDirectoryFactory. If a better option becomes available in a
newer Solr version, it will most likely be automatically chosen as long
as the value isn't explicitly configured.
Looking at the source, I cannot tell for sure whether NOIFS uses mmap,
but I suspect it does not. For nearly all use cases, you want a
directory implementation that uses mmap, which the NRTCaching
implementation does.
Changing the directory factory is very unlikely to cause any problems
with the existing index. But I am curious why you want to change
that... what have you encountered and why do you think you should go
with a non-default class?
If you have enough memory installed, the disk speed will have very
little impact on performance. Disk performance only becomes important
in situations where you do not have enough spare memory for effective
disk caching. Memory is faster than disk, even if the disk is extremely
fast SSD.
A directory implementation that uses mmap will be the fastest option.
Thanks,
Shawn
