I wanted to take a moment to address why ES30 SAS and ES30 shelves have certain configuration parameters. One particular parameter is that ES30 SAS shelves are only supported on the DD2500, DD4200, DD4500, and the DD7200 running DDOS 5.4.


Well why is this case? I mean if you look at some legacy systems, those systems support SAS from the controller to the SAS HBAs and even the ES30 shelves themselves have SAS backplanes. So why does the addition of SAS drives (ES30 SAS shelves) as opposed to SATA drives (ES30 shelves) introduce these parameters to the systems it supports?


The explanation is relatively straight forward. The other part of the parameter that can be missed in the shuffle is that DDOS 5.4 is a requirement as well. This is for a number of reasons:


  • SAS drives are true dual path so all activities and I/O don’t hit the same constraints as SATA drives with passive paths and active paths. DDOS 5.4 is designed for this hardware consideration.
  • Logging is enhanced with SAS drives. DDOS 5.4 takes advantage of that logging for failure analysis.
  • Ensures that drivers, firmware, etc. are supported and vetted properly for the total system configuration of the Data Domain.


To me that last bullet point is the most important. Being that Data Domain is a purpose built appliance it takes a high level of engineering and quality assurance to meet those demands– namely, data protection. For example, if an unsupported HBA is used in an older system trying to connect to use an ES30 SAS shelf which can’t keep up with the demand of the backup workload or causes system instability– then you’re in a world of hurt. Simply put DDOS 5.4 with certain Data Domain models are explicitly and purposefully built to guarantee data protection.