iXsystems X-Series (ISCSI)

Model number: X10
Storage Category: Software Defined Storage
Drive quantity, size, type: 

• 10x SAS 10TB HUH721010AL4200
• 1x SAS SSD 3.84TB XS3840SE70055
• 1x SAS SSD 960GB XS960SE70055

Storage Configuration: ZFS array of striped 2x HDD mirrors with 2 SSDs for read/write cache.
RAID 10 is the RAID level for the HDD. One SSD is used as a read cache and one SSD is used as a write cache to accelerate synchronous writes. Data is initially written to RAM, and then written to the SSD which completes the synchronous write and informs the sender the data is written to a non-volatile medium, and this is written to the RAID 10 array of HDDs.

Firmware version: TrueNAS SCALE 22.12.3
Connection protocol and speed: iSCSI, 10GbE
Additional support: All models and configurations of iXsystems X-Series with specifications equivalent or greater than the above

General product family overview:
TrueNAS is an Open Source storage operating system built on OpenZFS. The TrueNAS X-Series is a line of compact entry-level enterprise storage appliances. 

Vendor Settings:

• Caching used: One SSD is used as a secondary ZFS ARC device for read caching.One SSD is used as ZFS SLOG device.
• Read/write caching: Secondary ARC device acts as a read cache. ZFS uses ARC to cache recently and frequently accessed data. As new data is added to primary ARC the older data is moved to secondary ARC, which can be accessed faster than data off of the HDD array. In this test the 960GB SAS SSD was used as secondary ARC.
  ZFS SLOG is used for synchronous writes. Data is first written to RAM, then to the SLOG device, and then moved to the HDD array. For synchronous writes this allows the file system to confirm that data is written to non-volatile storage far faster than HDD allows. This test used the 3.84TB SAS SSD as SLOG, overprovisioned to 16GB.
• Multipathing / link aggregation used: No
• Array deduplication used in testing: No
• Array compression used in testing: yes