|
@@ -96,16 +96,11 @@ faster.
|
|
|
[discrete]
|
|
|
=== Use faster hardware
|
|
|
|
|
|
-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. Always use local storage,
|
|
|
-remote filesystems such as `NFS` or `SMB` should be avoided. Also beware of
|
|
|
-virtualized storage such as Amazon's `Elastic Block Storage`. Virtualized
|
|
|
-storage works very well with Elasticsearch, and it is appealing since it is so
|
|
|
-fast and simple to set up, but it is also unfortunately inherently slower on an
|
|
|
-ongoing basis when compared to dedicated local storage. If you put an index on
|
|
|
-`EBS`, be sure to use provisioned IOPS otherwise operations could be quickly
|
|
|
-throttled.
|
|
|
+If indexing is I/O-bound, consider increasing the size of the filesystem cache
|
|
|
+(see above) or using faster storage. Elasticsearch generally creates individual
|
|
|
+files with sequential writes. However, indexing involves writing multiple files
|
|
|
+concurrently, and a mix of random and sequential reads too, so SSD drives tend
|
|
|
+to perform better than spinning disks.
|
|
|
|
|
|
Stripe your index across multiple SSDs by configuring a RAID 0 array. Remember
|
|
|
that it will increase the risk of failure since the failure of any one SSD
|
|
@@ -115,6 +110,14 @@ different nodes so there's redundancy for any node failures. You can also use
|
|
|
<<modules-snapshots,snapshot and restore>> to backup the index for further
|
|
|
insurance.
|
|
|
|
|
|
+Directly-attached (local) storage generally performs better than remote storage
|
|
|
+because it is simpler to configure well and avoids communications overheads.
|
|
|
+With careful tuning it is sometimes possible to achieve acceptable performance
|
|
|
+using remote storage too. Benchmark your system with a realistic workload to
|
|
|
+determine the effects of any tuning parameters. If you cannot achieve the
|
|
|
+performance you expect, work with the vendor of your storage system to identify
|
|
|
+the problem.
|
|
|
+
|
|
|
[discrete]
|
|
|
=== Indexing buffer size
|
|
|
|