Preparing to Install Elasticsearch

By default, Liferay DXP 7.2 and its embedded Elasticsearch engine run in the same JVM. Although this enables out-of-the-box search, it’s only supported for development. For production use, Elasticsearch must run in a separate JVM. See the installation guide for information on installing a remote Elasticsearch cluster.

Because search engines benefit heavily from caching, their JVM memory profiles differ substantially from those of a JVM running Liferay DXP. Therefore, the two applications should always be kept separate in production environments.

The following sections provide a synopsis of Elasticsearch configurations for Liferay DXP 7.2. Prior to deployment, we strongly recommend reading Elastic’s documentation on production deployment.

Sizing Your Deployment

When sizing your Elasticsearch deployment, carefully consider CPU, memory, disk, and network capacity. To scale effectively and avoid using lots of machines, deploy Elasticsearch on medium to large machines (for example, machines with two to eight CPUs). Avoid running multiple Elasticsearch JVMs on the same operating system.

CPU

We recommend allocating at least eight total CPU cores to the Elasticsearch engine, assuming only one Elasticsearch JVM is running on the machine.

Memory

At least 16 GB of memory is recommended, with 64 GB preferred. The precise memory allocation required depends on how much data is indexed. For index sizes 500 GB to 1 TB, 64 GB of memory suffices.

Disk

Search engines store their indexes on disk, so disk I/O capacity can impact search performance. Deploy Elasticsearch on SSD whenever possible. Otherwise use high-performance traditional hard disks (for example, 15k RPM). In either case, consider using RAID 0.

Avoid using Network Attached Storage (NAS) whenever possible as the network overhead can be large. If you’re using public cloud infrastructure like Amazon Web Services, use instance local storage instead of network storage, such as Elastic Block Store (EBS).

Maintain 25 percent more disk capacity than the total size of your indexes. If your index is 60 GB, make sure you have at least 75 GB of disk space available. To estimate the disk space you need, you can index a representative sample of your production content and multiply that size by the fraction of your production content that it represents. For example, index 25 percent of your production content and then multiply the resulting index size by four. Keep in mind that indexing a 1 MB file doesn’t result in 1 MB of disk space in the search index.

Cluster Size

While Liferay DXP can work with an Elasticsearch cluster comprised of one or two nodes, the minimum cluster size recommended by Elastic for fault tolerance is three nodes.

Networking

Elasticsearch relies on clustering and sharding to deliver fast, accurate search results, and thus requires a fast and reliable network. Most modern data centers provide 1 GbE or 10 GbE between machines.

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