Bypassed physical disk -- using non-Dell drives in Dell SAN?

SINC_dmack
SINC_dmack used Ask the Experts™
on
For the last several years, we have been reselling Dell servers and populating them with much-less-expensive-than-buying-from-Dell aftermarket SSDs.  We are currently in the process of setting up a Dell PowerVault MD3820i SAN, and assumed that we'd be okay with non-Dell drives.  We are attempting to utilize Samsung 1TB 860 EVO drives.  The SAN indicates the status of all of the SSDs as "bypassed physical disk".  Some quick Googling has returned multiple results that indicate that the SAN requires Dell-branded drives.  That would be a significant hindrance to this project, both due to cost (haven't priced Dell 1TB SSDs yet but I bet they cost their weight in gold) and timeliness (client was hoping for us to deliver the SAN in the near future).  

So, this post is kind of a Hail Mary to see if there's any way to get these non-Dell drives working in this SAN, or if we need to start sourcing Dell SSDs and filling out RMA forms for these Samsungs.
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Top Expert 2014
Commented:
MD series has always needed certified disks. You shouldn't be using 1TB Samsung SSDs anyway, their enterprise ones are 960GB leaving the remaining space hidden for background garbage collection which is needed with hardware RAID as there is no TRIM/UNMOUNT.

If you are using SATA disks they also need an interposer in the caddy to convert the SATA device into a dual-ported SAS one.

Author

Commented:
Ignoring the TRIM issue for the moment, isn't an interposer just a physical adapter? If the Samsung 1TB SSDs are recognized (albeit bypassed) by the SAN, then why would an interposer be needed?
Top Expert 2014

Commented:
An interposer is required for SATA drives as they only have one port and for dual controllers you have to have two ports, one goes to each controller. SAS (except for some very early disks) are all dual-ported natively. LAck of interposer with SATA disks in a MDxxx will put them in bypass.
Should you be charging more for IT Services?

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden using our free interactive tool and use it to determine the right price for your IT services. Start calculating Now!

Author

Commented:
So, you think there's a decent chance that interposers will allow the SATA SSDs to work with the SAN?  

If so, the next question becomes.. what interposers do I need and how are they installed?  I'm not sure how they'd go in the caddies.. they're 2.5" caddies and there's not really any space I'm aware of that could allow for any additional hardware.
Top Expert 2014

Commented:
Hmm, there's no 2.5" interposer, so the thing is SAS only. Only Interposer was the 3Gb LFF one for MD3000

 https://www.dell.com/ee/business/p/powervault-md3820i/pd - no mention of SATA on that page even though the owner's manual does mention SATA because bits are copied from older versions.

Author

Commented:
Looks like we've got no choice but to go with compatible SAS SSDs.  Fortunately we've been able to find refurbished SSDs and "like new" pulls for reasonable money, and fortunately the client is understanding of the issue.  Turns out that even the "read intensive" SAS SSDs have a wildly longer TBW than the Samsung 860 EVOs.

Dell part number 086DD is a Samsung PM1633a-based 1.92TB drive with an Endurance TBW (terabytes written) rating of 3504.
https://i.dell.com/sites/csdocuments/Shared-Content_data-Sheets_Documents/en/dell-poweredge-sas-ssd-performance-specifications.pdf

Samsung 860 EVO 1TB has a TBW of 600, and the 2TB has a TBW of 1200.  
https://www.samsung.com/semiconductor/minisite/ssd/product/consumer/860evo/

So, the Dell 086DD has a TBW rating that is almost 6x greater than the Samsung 1TB and almost 3x greater than the Samsung 2TB.  Even if they are 50% used up, that’s still more than 1700 TBW remaining, which is still almost triple the Samsung 1TB’s rating and 50% greater than the Samsung 2TB’s rating.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial