Home > Storage > PowerScale (Isilon) > Product Documentation > Data Efficiency > Next-Generation Storage Efficiency with Dell PowerScale Inline Data Reduction > Writes to a mixed F810 cluster
Figure 9 below depicts a file write in a mixed cluster environment. A client connects to an H400 node and writes a file with a path-based file pool policy that directs the file to an F810 nodepool. In this scenario, the H400 node first scans the incoming data for zero block removal or deduplication opportunities.
Zero block elimination and inline deduplication will only be enabled on nodes that have local drives in a disk pool with the data reduce flag set.
The data reduce flag will only be set on F910, F900, F810, F710, F600, F210, F200, H700/7000, H5600, and A300/3000 disk pools and therefore zero block elimination and inline deduplication will only be performed on those platforms. When found, any zero blocks are stripped out and any matching blocks are deduplicated.
Next, the data is divided into 128 KB compression chunks as usual. However, since the H400 node does not have an FPGA offload card, it instead performs compression on the chunks in software.
Unlike inline deduplication, compression does not require the initiator node to be a member of a disk pool with the data reduce flag set. If the target disk pool for the write has data reduction set and the cluster has inline compression enabled, compression will be performed.
A different compression algorithm is used to help minimize the performance impact. Each compressed chunk is then FEC protected and the H400 uses its write plan to place blocks on the participant nodes. The chunks are written in compressed form over the back-end network to the appropriate F810 nodes.