Advanced Technology for Maximum Performance


 

Memory Requirements


ESS memory usage can range from moderate to staggering, depending on the size of the array, the "memory model" in use, and the mode that ESS is operating in. In most cases, memory usage, although signifigant, should not pose a barrier to using ESS.

Linear Mode

In linear mode, there are two ESS options that impact memory usage.

Standard Linear Mode

In this mode, the amount of memory needed depends on the physical size of the array and the logical size of the available addressing space.

For arrays < 4 TB in size, multiply the logical size by 0.1%. Thus a 2TB array with 1.8TB available will need 1.8GB of RAM.

For arrays > 4TB in size, multiple the logical size by 0.125%. Thus an 8 TB array with 7.2TB available will need 9GB of RAM.

Linear Mode with Error Detection

In this mode, a non cryptographic hash is maintained along with each 4K block. This allows the driver to "verify" that every block written is "correct".

For arrays < 1PB in size, multiply the logical size by 0.2%. Thus a 16 TB array with 14.4TB available will need 28.8GB of RAM.

Compressed Mode

Compressed Mode works very similarly to Linear Mode with an option for Error Detection. With compressed mode, it is likely that the Logical size will actually be larger than the physical size.

Standard Compressed Mode

For arrays < 256 GB in size, multiply the logical size by 0.125%. Thus a 200GB array with 180GB available will need 225 MB of RAM.

For arrays < 64 TB in size, multiply the logical size by 0.150%. Thus a 20TB array with 30TB available will need 45 GB of RAM.

For arrays < 16 PB in size, multiple the logical size by 0.175%. Thus a 100TB array with 200TB available will need 350 GB of RAM.

Compressed Mode with Error Detection

For arrays < 64 TB in size, multiply the logical size by 0.2%.

For arrays < 16 PB in size, multiple the logical size by 0.225%.

Deduplication Mode

Deduplication mode, by itself, is not currently supported. Deduplication and Compressed Mode can be used with the compression level set to "none" to emulate this.

Deduplication and Compression Mode

Dedupe and Compressed (DDC) mode can have very high memory usage value, especially for large arrays with large "data reduction" factors. For this reason, several memory modes are available to mitigate memory issues.

Further documentation on DDC memory usage is in work. Contact support@easyco.com if you wish to discuss particular configuration.

 







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