Indexing speed and SSD hardware

[tlandelin (Travis Andelin)]

In Tune for indexing speed | Elasticsearch Guide [master] | Elastic it says

If indexing is I/O bound, you should investigate giving more memory to the filesystem cache (see above) or buying faster drives. In particular SSD drives are known to perform better than spinning disks....

I've been experimenting with indexing with SSD drives, but I'm not finding significant improvement in indexing speed. I'm left to conclude that likely my indexing is not I/O bound.

How can I tell for sure whether indexing is I/O bound?

Also, are there any recommended settings for indexing when backed by SSD drives?

[Christian_Dahlqvist]

Are you using locally attached SSDs? What does disk utilisation and cpu usage look like during indexing?

[tlandelin (Travis Andelin)]

Yes, SSDs are locally attached.

With our regular HDD cluster, during indexing (using sar to measure), CPU averages 15% and is blocked by disk I/O on average 1.5% of the time. Measurements include search traffic.

[rugenl (Len Rugen)]

Indexing should be "write" bound before "read" bound, memory cache may not help write rate.

Are these SATA or SAS SSD? What OS and filesystem?

[tlandelin (Travis Andelin)]

Disks are SAS. Running debian linux and using xfs