FME Form: 2024.2
When FME runs a large, multi-dataset translation, it often requires a lot of temporary disk space. This is particularly true when running a Dataset Fanout, because there is no guarantee that the features will arrive at the fanout in a single dataset group. Therefore, FME has to write out all of the datasets to temporary storage, and then fan them out afterward. The amount of available disk space is important, but on a performance level, you might be more concerned about the speed of all this disk activity.
Many of the FME temporary files are created when caching data for larger datasets or for display in the FME Data Inspector. Using a faster hard drive can make a significant difference to the FME translation if disk cache I/O speeds are improved. An example would be if you have an SSD (Solid-State Drive) on your computer. These are typically quite a bit faster than traditional HHD drives, so if you can point your FME_TEMP to an SSD then you'll see a bit of a performance increase when working with larger datasets.
Where possible, set your temporary folder to point to the fastest disk you have available.
Note This FME Community article tells you how to set the FME_TEMP environment variable. (In Windows 7, look under Control Panel > System > Advanced > Environment Variables).
Usage Notes
Don't set your temporary folder on the same disk that the operating system uses; FME might be slowed down by the operating system writing to the same disk at the same time.
Try to set the temporary folder to a disk that has a large amount of free space – it won't improve the speed, but it might prevent a large translation from failing due to a lack of disk space.
Java VM Loading
Note These settings are for FME Plug-ins written in Java.
These environment variables allow you to specify memory available to Java Plugins:
- FME_JVM_MIN_HEAP_SIZE: Initial heap size for initializing the JVM. If unset, the default value is 1024K.
These variables must be set in multiples of 1024 and greater than 1 MB. To indicate kilobytes, megabytes, or gigabytes, append k or K, m or M, or g or G respectively. For example, any of these values is acceptable:
6291456
6144k
6m
- FME_JVM_MAX_HEAP_SIZE: Maximum heap size for initializing the JVM. If unset, the default value is 16384K.
These variables must be set in multiples of 1024 and greater than 2 MB. To indicate kilobytes, megabytes, or gigabytes, append k or K, m or M, or g or G respectively. For example, any of these values is acceptable:
83886080
81920k
80m
"temporary directory"