SAS SSD - Bang for buck?

[doofoo]

So we are looking at a few different dual controller devices (QNAP ES1640DC v2, QSAN, etc).

The re-occuring theme is that they only support SAS drives (or SATA with MUX board, but seems that some SMART data does not pass along with other issues).

Does anyone have any go to 1TB - 2TB SAS SSD's they would recommend (bang for buck). Our workload doesn't need a crazy TBW/endurance as it's read heavy on most things.

Jumping from SATA to SAS is a big pill to swallow. Ugh..

Alternatively, does anyone have any feedback with smaller SSD's as cache on ES1640DC's serving back-end spindles?

 

[OneOfMany07]

I'm amazed you're required to use SAS. I thought part of the point of SAS was that it was backwards compatible. I mean you'd lose the benefits (better error encoding features, etc), but it should function from what I read. I should say I have no experience with those devices you list, and am a somewhat newbie to all of this ZFS NAS server stuff.

Source below from Serial Attached SCSI - Wikipedia claiming...

"SAS offers backward compatibility with SATA, versions 2 and later. This allows for SATA drives to be connected to SAS backplanes. The reverse, connecting SAS drives to SATA backplanes, is not possible."

Adaptec - SAS & SATA Compatibility

"SATA connector signals are a subset of SAS signals, enabling the compatibility of SATA devices and SAS adapters. SAS drives will not operate on a SATA adapter and are keyed to prevent any chance of plugging them in incorrectly.

In addition, the similar SAS and SATA physical interfaces enable a new universal SAS backplane that provides connectivity to both SAS drives and SATA drives, eliminating the need for separate SCSI and ATA drive backplanes. This consolidation of designs greatly benefits both backplane manufacturers and end-users by reducing inventory and design costs."

 

[Terry Kennedy]

So we are looking at a few different dual controller devices (QNAP ES1640DC v2, QSAN, etc).

The re-occuring theme is that they only support SAS drives (or SATA with MUX board, but seems that some SMART data does not pass along with other issues).

"dual controller" and "SATA mux" sounds like they need a dual-port drive. Dual port is only (optionally) available on SAS drives, not SATA ones. Dual-port SAS drives (3.5"/2.5", not the various other form factors) have the second set of port pins located on the other side of the keying area between the power and data parts of the connector.

Jumping from SATA to SAS is a big pill to swallow. Ugh..

I've preferred SAS for years. SAS gets all the cool features before SATA (if SATA ever gets them - I doubt we'll ever see SATA dual-port, for example). If you're buying new, SAS isn't that much more expensive than SATA (from the same drive family from the same manufacturer) and you always get the best warranty. Of course, if you are comparing new Dell- / HPE- / whatever-certified SAS drives against WD Reds or similar, yes there is a huge price difference.

4Kn sectors are a bigger hurdle than SAS vs. SATA from a controller / OS point of view.